i. The remains were interred on the foothills or mountainsides, ii. A mining region provided the soil, iii. Dirt was transferred from a subsurface location, iv. The soil had been dug up and compacted using a shovel.
The soil samples collected from the burial contained rocks and minerals that are typically found in mountainous areas, which lends credence to the assertion that the victims were interred in the highlands or foothills of the mountains.
ii. Soil was collected from a mining area: The discovery of iron, copper, and other minerals typical of mining sites lends credence to this argument.
iii. Subsurface dirt was moved: This assertion is confirmed by the presence of a layer of subsoil in the soil samples that was distinct from the top soil.
iv. The soil had been dug up and compacted using a shovel: The presence of both loose and compacted soil in the soil samples lends credence to this assertion.
v. The earth on the shovel and at the gravesite matched each other: The fact that the shovel and burial dirt samples both contained identical minerals and had comparable chemical compositions lends credence to this assertion.
vi. Animals played a role in the crime's resolution: This assertion is reinforced by the fact that the grave's surroundings had been disturbed by animals, which led detectives to the location of the grave.
b) The various methods of examination employed to contrast the soil discovered on the shovel and the soil discovered at
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How many silicon atoms are in a piece of glass weighing 6.240
Assuming that the glass is made entirely of silicon dioxide (SiO2), which is a common component of glass, we can calculate the number of silicon atoms based on the molecular weight of SiO2 and the weight of the glass.
How many silicon atoms are in a piece of glass weighing 6.240?The molecular weight of SiO2 is approximately 60 g/mol. Therefore, 6.240 g of SiO2 corresponds to:
6.240 g SiO2 × (1 mol SiO2/60 g SiO2) = 0.104 mol SiO2
Since each molecule of SiO2 contains one silicon atom, the number of silicon atoms in the piece of glass can be calculated by multiplying the number of moles of SiO2 by Avogadro's number (6.022 × 10^23 atoms/mol):
0.104 mol SiO2 × (6.022 × 10^23 atoms/mol) = 6.26 × 10^22 silicon atoms
Therefore, there are approximately 6.26 × 10^22 silicon atoms in a piece of glass weighing 6.240 g, assuming the glass is made entirely of SiO2.
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Part 1. A lightly inflated balloon is placed in a freezer. Explain the change to the size of the balloon based on the kinetic molecular theory.
Part 2. What would most likely happen to the balloon if it was instead kept outside in the sun for some time? Explain your answer based on the kinetic molecular theory.
In both cases, assume the balloon is tied tight enough so that air does not escape.
Part 1: When a lightly inflated balloon is placed in a freezer, the temperature of the air molecules inside the balloon decreases. According to the kinetic molecular theory, the volume of a gas is directly proportional to its temperature. As the temperature of the air molecules inside the balloon decreases, the average kinetic energy of the air molecules also decreases, causing the gas to contract. This contraction leads to a decrease in the volume of the gas inside the balloon, which causes the balloon to shrink in size.
Part 2: If the balloon is instead kept outside in the sun for some time, the temperature of the air molecules inside the balloon will increase. According to the kinetic molecular theory, an increase in temperature leads to an increase in the average kinetic energy of the gas molecules, causing them to move faster and collide more frequently. This increased collision frequency leads to an increase in pressure, which causes the balloon to expand in size. Therefore, the balloon will most likely get bigger when it is exposed to the heat of the sun.
Answer:
simple answer
Explanation:
part 1: if the balloon's temperature decreases so does the air molecules within it. The gas contracts because it's in a seal place, causing the balloon to shrink.
part 2: the balloon is exposed to heat, so the temperature is obviously going to increase as well as the air molecules. Gas molecules are moving rapidly causing the balloon to expand.
a) In separate containers, equal volumes of 0.1 M HCl and 0.1 M HC2H3O2 (weak acid) are titrated with 0.1 M NaOH. Which of the following is true?
a)the pH at the equivalence point is greater for HC2H3O2 than for HCl
b)HCl is a strong acid and requires more moles NaOH to reach the equivalence point
c)the pH at the half equivalence point is the same for both solutions
d)the initial pH is the same for both solutions
e)all these statements are false
b)What concentration of NaCN must be added to a 0.5 M HCN solution to produce a buffer solution with pH 7.0? Ka = 6.2 x 10–10 for HCN.
a)0.49 M
b)6.9 x 10-5 M
c)3.3 M
d)0.0031 M
e)0.22 M
A) All these statements are false. Option E is correct.
B) 0.22 M NaCN must be added to a 0.5 M HCN solution to produce a buffer solution with a pH of 7.0. The Ka for HCN is 6.2 x 10–10. So the correct option is E.
A) a. The pH at the equivalence point is greater for HC2H3O2 than for HCl - FALSE. The pH at the equivalence point is the same for both weak and strong acids when titrated with a strong base such as NaOH.
b. HCl is a strong acid and requires more moles NaOH to reach the equivalence point - FALSE. Both HCl and HC2H3O2 require the same amount of moles of NaOH to reach the equivalence point.
c. The pH at the half equivalence point is the same for both solutions - FALSE. The pH of the half equivalence point is different for HCl and HC2H3O2. For HCl, the pH of the half equivalence point is 7, whereas for HC2H3O2, the pH of the half equivalence point is greater than 7.
d) The initial pH is the same for both solutions - FALSE. The initial pH of the two solutions are different due to the different properties of the two acids.
e) All these statements are false - TRUE. All of the statements above are false. Option E is correct.
B) To answer the second part of the question, 0.22 M NaCN must be added to a 0.5 M HCN solution to produce a buffer solution with a pH of 7.0. The Ka for HCN is 6.2 x 10–10. In order to calculate the amount of NaCN required, use the Henderson-Hasselbalch equation:
pH = pKa + log [NaCN]/[HCN]
Rearranging and solving for [NaCN]:
[NaCN] = 10^(7-6.2) x 0.5 = 0.22 M
So the correct option is E.
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Which is an example of Conduction?
A Warm air rising, cooling at high temperatures, and then falling back to lower elevations.
B Warming your hands by a fire.
C The sun warming your face
D Burning your mouth on a hot spoon
Burning your mouth on a hot spoon(option D) is an example of heat transfer through conduction, as the spoon is in direct contact with your mouth.
What is conduction?Conduction is the transfer of heat or electrical energy between two objects that are in direct contact with each other, or between two parts of the same object that are at different temperatures.
In conduction, the energy transfer occurs due to the collision of molecules in the objects or materials. When two objects are in contact, the molecules of the warmer object vibrate more rapidly, colliding with the molecules of the cooler object, which have less energy.
These collisions transfer thermal energy from the warmer object to the cooler object, until both objects reach the same temperature.
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a) The ionization constant for water (Kw) is 5.476 x 10-14 at 50 oC. Calculate [H3O+], [OH-], pH, and
pOH for pure water at 60oC.
b) Look at the following table with temperature, Kw, and pH values for pure water.
Temp. (oC)
Kw
pH
0
0.114 x 10-14
7.47
10
0.293 x 10-14
7.27
20
0.681 x 10-14
7.08
25
1.008 x 10-14
7.00
40
2.916 x 10-14
6.77
60
9.550 x 10-14
6.51
100
51.3 x 10-14
6.14
Notice that the pH falls as the temperature increases.
i) Does this mean that pure water becomes more acidic as the temperature rises? _______
ii) The reason for my answer is in pure water…(choose the correct letter from 1 - 5)._______
1. the pH becomes less than 7 as the temperature rises.
2. there are less H3O+ ions created as the temperature increases.
3. there are more H3O+ ions created as the temperature increases.
4. there are always the same # of hydronium and hydroxide ions even if the pH changes.
5. the OH- ions are evaporated as the temperature rises.
A) To solve this problem, we can use the formula for the ionization constant of water:
Kw = [H3O+][OH-]
At 50 oC, Kw = 5.476 x 10-14. We can assume that [H3O+] and [OH-] are equal since we are dealing with pure water.
Therefore,
[H3O+] = [OH-] = sqrt(Kw) = sqrt(5.476 x 10-14) = 7.40 x 10-8 mol/L
pH = -log[H3O+] = -log(7.40 x 10-8) = 7.13
pOH = -log[OH-] = -log(7.40 x 10-8) = 7.13
To find the values for pure water at 60oC, we can use the new value of Kw at that temperature:
Kw = 9.550 x 10-14
[H3O+] = [OH-] = sqrt(Kw) = sqrt(9.550 x 10-14) = 3.09 x 10-7 mol/L
pH = -log[H3O+] = -log(3.09 x 10-7) = 6.51
pOH = -log[OH-] = -log(3.09 x 10-7) = 6.51
b) i) No, it does not mean that pure water becomes more acidic as the temperature rises.
ii) The correct answer is 2. As the temperature increases, the ionization of water increases and more H3O+ and OH- ions are formed. However, since the concentration of H2O is also decreasing due to the increase in temperature, the increase in ionization does not result in an increase in [H3O+] and pH actually decreases.
number of atoms of elements are found in the formula 3He2O4PH
The number of atoms of each element found in the formula 3He₂O₄PH are: 6 Helium atoms, 4 Oxygen atoms, 1 Phosphorus atom, and 1 Hydrogen atom.
What is the number of atoms of element in the compound?The formula 3He₂O₄PH represents a molecule containing the elements Helium (He), Oxygen (O), Phosphorus (P) and Hydrogen (H).
The subscripts in the formula indicate the number of atoms of each element present in one molecule of the compound.
Therefore, the number of atoms of each element in 3He₂O₄PH is:
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How would your calculated molarity of NaOH solution be affected (too high_ too low or no change) by each of the following The burette is not rinsed with the solution before it is filled: b) You go past the endpoint in the titration: Some of acid solution splashes out of the flask during the titration Using water to rinse the inner sides of the flask:
This will have no effect on the molarity of the NaOH solution, as the amount of NaOH will remain the same.
The calculated molarity of NaOH solution would be affected (too high, too low, or no change) in the following ways
:If the burette is not rinsed with the solution before it is filled, the calculated molarity of NaOH solution will be too low. This is because impurities present in the burette could dilute the solution, resulting in an incorrect molarity measurement.If you go past the endpoint in the titration, the calculated molarity of NaOH solution will be too high. This is because the added base has exceeded the amount required to neutralize the acid.
As a result, the molarity of the NaOH solution will appear higher than it is in reality. If some of the acid solution splashes out of the flask during the titration, the calculated molarity of NaOH solution will be too high. This is because the acid solution lost its concentration, resulting in the molarity being higher than it should be.
Using water to rinse the inner sides of the flask will not affect the calculated molarity of NaOH solution. This is because water is neutral and does not have the ability to react with the solution, which means that the molarity of the NaOH solution will remain unchanged.
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Gaseous heptane (C7H17) reacts with oxygen gas to produce gaseous carbon dioxide and liquid water.
Answer:
To balance this equation, we need to know the coefficients for each reactant and product. The balanced equation for the reaction is:
C7H17 + 11O2 → 7CO2 + 8H2O
This equation indicates that one molecule of heptane reacts with 11 molecules of oxygen gas to produce seven molecules of carbon dioxide and eight molecules of water.
The stoichiometric coefficients in the balanced equation tell us the relative amounts of each reactant and product in the reaction. For example, one molecule of heptane reacts with 11 molecules of oxygen gas to produce seven molecules of carbon dioxide and eight molecules of water. Therefore, if we have 1 mole of heptane, we need 11 moles of oxygen gas to completely react with it, and we will produce 7 moles of carbon dioxide and 8 moles of water.
To determine the amount of each product that will be produced when a given amount of reactants is used, we need to use stoichiometry. We can convert the mass of heptane and oxygen gas to moles, and then use the stoichiometric coefficients in the balanced equation to calculate the amount of carbon dioxide and water that should be produced.
For example, if we have 10 grams of heptane and 50 grams of oxygen gas, we can calculate the amount of each product that should be produced as follows:
1. Calculate the number of moles of each reactant:
moles of heptane = 10 g / 100.21 g/mol = 0.0999 mol
moles of oxygen gas = 50 g / 31.9988 g/mol = 1.562 mol
2. Determine the limiting reactant:
Using the stoichiometric coefficients in the balanced equation, we can see that 1 mole of heptane reacts with 11 moles of oxygen gas. Therefore, the limiting reactant is heptane, because we only have 0.0999 moles of it, whereas we have 1.562 moles of oxygen gas.
3. Calculate the theoretical yield of each product:
moles of CO2 = moles of heptane × (7 moles of CO2 / 1 mole of C7H17) = 0.6993 mol
moles of H2O = moles of heptane × (8 moles of H2O / 1 mole of C7H17) = 0.7992 mol
mass of CO2 = moles of CO2 × molar mass of CO2 = 0.6993 mol × 44.01 g/mol = 30.77 g
mass of H2O = moles of H2O × molar mass of H2O = 0.7992 mol × 18.015 g/mol = 14.39 g
Therefore, if we have 10 grams of heptane and 50 grams of oxygen gas, the theoretical yield of carbon dioxide is 30.77 grams and the theoretical yield of water is 14.39 grams. Note that the actual yield may be different, depending on the conditions of the reaction and the efficiency of the reaction.
1) what is the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29% oxygen? worksheet
The empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29% oxygen is CH2O.
To calculate this, you need to first convert the percentage composition into mass composition. This is done by multiplying the percentages by the molecular weight of each element.
Carbon: 65.5% x 12 g/mol = 0.786 g/mol
Hydrogen: 5.5% x 1 g/mol = 0.055 g/mol
Oxygen: 29% x 16 g/mol = 0.464 g/mol
Now that you have the mass composition, you can calculate the moles of each element by dividing the mass of each element by its molar mass.
Carbon: 0.786 g/mol / 12 g/mol = 0.065 mol
Hydrogen: 0.055 g/mol / 1 g/mol = 0.055 mol
Oxygen: 0.464 g/mol / 16 g/mol = 0.029 mol
Finally, divide each element's moles by the smallest moles to get the empirical formula.
Carbon: 0.065 mol / 0.029 mol = 2.24 = 2 mol
Hydrogen: 0.055 mol / 0.029 mol = 1.90 = 1 mol
Oxygen: 0.029 mol / 0.029 mol = 1.00 = 1 mol
Therefore, the empirical formula of the molecule is CH2O.
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Polar air is often described as dry even though the relative humidity is high. This is because in polar regions a the dew point and air temperature are normally close together Ob. there is a large separation between dew point and air temperature c. the air has a high absolute humidity Od there is a high dew point temperature
Polar air is often described as dry because there is a large separation between the dew point and air temperature. This occurs because the air is usually very cold and has a low absolute humidity.
Polar air is often described as dry even though the relative humidity is high. This is because in polar regions there is a large separation between dew point and air temperature.In polar regions, the air is very cold, and therefore has very little moisture. This means that the relative humidity of the air is very high, but the actual amount of moisture in the air is very low. This is because cold air cannot hold as much moisture as warm air. When the temperature of the air drops, the amount of moisture that it can hold also decreases.
As a result, the relative humidity of the air increases, even though the actual amount of moisture in the air is very low.
The relative humidity is high because the dew point and air temperature are close together. This means that the amount of water vapor in the air is low, making it feel dry.
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What is the hybridization around the nitrogen atom indicated with #1?
Because the marked atom has a single electron pair, one sp bonded link, and one created by overlapping p orbitals, it is sp bridged. Nitrogen has therefore undergone sp fusion.
What does atom 1's hybridization entail?The hybridized of the atom labelled no.1 is sp3. Since there are two lone pairings of electrons, two bonds, and four groups surrounding this atom, their hybridization is sp3. Just under 109.5 degrees make up the bond angle.
What is the given nitrogen atom's hybridization?The nitrogen has 4 sp3 hybrid orbitals since it is sp3 hybridised. To create the two N-H sigma bonds, two of the sp3 hybridised orbitals overlap with hydrogen s orbitals.
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50.0 g of sample B has 31.65g Xe and 18.35 g F. What is the percent by mass Xe in sample B?
According to the question the percent by mass Xe in sample B is 63.3%.
What is mass?Mass is a measure of the amount of matter in an object. It is usually measured in kilograms or grams, but it can also be expressed in other units such as pound or ton. Mass is different than weight, which is a measure of the force of gravity acting on an object. Mass is constant regardless of the gravity a certain object is exposed to, while weight will change depending on the gravity.
The percent by mass Xe in sample B is equal to the mass of Xe in sample B divided by the total mass of sample B multiplied by 100. This equation can be written as:(mass of Xe in sample B / total mass of sample B) × 100
Plugging in the values for the mass of Xe in sample B (31.65g) and the total mass of sample B (50.0g), we get:
(31.65 g / 50.0 g) × 100 = 63.3%
Therefore, the percent by mass Xe in sample B is 63.3%.
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The equilibrium constant expression for a reaction is [CO2]2/[SO2]2[O2]. What is the balanced chemical equation for the overall reaction if one of the reactants is Na2CO3(s).
Answer:
The given equilibrium constant expression is for the reaction:
2 CO2 (g) + 2 SO2 (g) + O2 (g) ⇌ 2 CO2 (g) + 2 SO3 (g)
To incorporate Na2CO3 (s) into this reaction, we need to balance the equation for the reaction involving Na2CO3:
Na2CO3 (s) → Na2O (s) + CO2 (g)
Now, we can combine the two equations by cancelling out CO2 (g) on both sides:
Na2CO3 (s) → Na2O (s) + CO2 (g)
2 CO2 (g) + 2 SO2 (g) + O2 (g) ⇌ 2 CO2 (g) + 2 SO3 (g)
Adding the two equations together, we get the balanced chemical equation for the overall reaction:
Na2CO3 (s) + 2 SO2 (g) + O2 (g) → Na2O (s) + 2 SO3 (g)
The equilibrium constant expression remains the same as [CO2]2/[SO2]2[O2], as CO2 is not involved in the overall reaction.
Consider the reaction between aqueous solutions of potassium hydroxide and chromium (III) chloride. Based on your balanced equation for this reaction, answer the following questions: 1) What are the spectator ions in this reaction? and 2) What is the formula for the precipitate formed in this reaction? 3) What is the sum of all the coefficients in the net ionic equation for this reaction? Net lonic Equati....pdf Hydrocarbon C....pdf
The net ionic equation for the given reaction is: 1 Cr3+(aq) + 3OH-(aq) → Cr(OH)3(s)
2. The formula for the precipitate formed in this reaction is Cr(OH)3.
3. The sum of all coefficients in the net ionic equation is 4.
Consider the reaction between aqueous solutions of potassium hydroxide and chromium (III) chloride. The balanced chemical equation for the given reaction is:KOH(aq) + CrCl3(aq) → KCl(aq) + Cr(OH)3(s)1) Spectator ionsThe ions that do not take part in the reaction are known as spectator ions.
These ions are present on both sides of the equation without undergoing any chemical changes.The ionic equation for the given reaction is:3K+(aq) + 3OH-(aq) + Cr3+(aq) + 3Cl-(aq) → 3K+(aq) + 3Cl-(aq) + Cr(OH)3(s)The spectator ions are K+ and Cl-.2)
PrecipitateThe precipitate is formed when the two reactants are combined together, and it can be identified from the ionic equation. In this reaction, the precipitate is formed when KOH is added to the aqueous solution of chromium(III) chloride.The formula for the precipitate formed in this reaction is Cr(OH)3.3) Sum of all coefficientsThe net ionic equation represents the actual chemical change occurring in the reaction.
The spectator ions are removed, and only the ions that participate in the reaction are shown. The net ionic equation for the given reaction is:Cr3+(aq) + 3OH-(aq) → Cr(OH)3(s)The sum of all coefficients in the net ionic equation is 4.
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Calculate the pH of a solution prepared by mixing equal volumes of 0.20 M methylamine (CH3NH2 Kb 3.7x 10-4) and 0.60 M CH3NH3Cl.
The pH of the methylamine solution is 10.11. It is calculated using the expression for pH of the solution.
Methylamine is classified as an example of weak base with K=3.7×10−4. These base partially ionizes in aqueous medium producing hydroxide ion and its conjugate acid, methylammonium that is a weak acid. some of the examples of weak base includes ammonia and dimethylamine.
pH is defined as the acidity denoting "potential of hydrogen" is a scale used to specify the acidity or basicity of an aqueous solution. According to the pH scale acidic solutions are measured to have lower pH values than basic or alkaline solutions. The pH of the solution containing methylamine and methylammonium chloride is given in the terms of,
pH = pKa + log[CH3NH2] / [CH3NH+3]
=−log1.0×10−14 / 3.7×10−4 + log 0.22M / 0.63M
=10.11
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Science Grade 5. 5 Importance of sound
The movement of airborne particles is caused by every vibrating item. This motion, which lasts until the particle runs out of power, produces sound waves.
Why is sound significant to children?The development of children includes sound from the time they are born. White noise, lullabies, and the voices of their parents are soothing to infants, and as they get older, other sounds aid in their connection and learning.
A good brief note It is what?Plasma molecules of a air surrounding an item vibrate as a result. Nearby molecules that come into contact with these molecules vibrate as a result. They consequently run across additional air molecules in the area.
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The correct question is
Explain the importance of sound in our daily life .
1. Choose the atom with the larger electronegativity.
Select one:
a. Rubidium
b. Caesium
2. Choose the atom with the larger electronegativity.
Select one:
a. Boron
b. Indium
3. Choose the atom with the larger first ionization energy.
Select one:
a. Titanium
b. Manganese
4. Choose the atom with the larger first ionization energy.
Select one:
a. Silicon
b. Tin
5. Choose the atom with the smaller atomic size.
Select one:
a. Nitrogen
b. Bismuth
6. Choose the atom with the smaller atomic size.
Select one:
a. Arsenic
b. Bromine
Indium has higher electronegativity as compare to Indium, because boron has smaller atomic size.
What is Electronegativity?
Electronegativity is a measure of an atom's ability to attract electrons towards itself when it is chemically combined with another atom. It is a relative scale that ranges from 0.7 to 4.0, with fluorine having the highest electronegativity value of 4.0. The electronegativity of an atom depends on several factors, including the number of protons in its nucleus, its distance from the nucleus, and the shielding effect of inner electrons. The electronegativity value of an element is useful in predicting the polarity of bonds formed between atoms and the distribution of electrons within a molecule.
Boron and Indium are both metallic elements in the same period of the periodic table. However, boron has a smaller atomic size and higher effective nuclear charge than indium. This makes boron a more electronegative element than indium, as the electrons in boron's valence shell are more strongly attracted towards its nucleus than in indium. Therefore, boron has a greater electronegativity than indium.
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what happens when zinc chloride reacts with potassium hydroxide and what formed?
Answer:
when the solution of potassium hydroxide and zinc chloride are mixed,the double-displacement reaction occur ,resulting in precipitation and the reaction forms potassium chloride and zinc hydroxide .
State whether M=[-1 -4] has an inverse. If the inverse exists, find it.
No, the inverse of the matrix represented as M=[-1 -4] does not exist.
What is an inverse matrix?An inverse matrix is a square matrix that, when multiplied by its original matrix, yields the identity matrix. It allows for solving linear equations involving the original matrix.
To determine if a matrix has an inverse, we can compute its determinant. If the determinant is nonzero, then the matrix has an inverse; if the determinant is zero, then the matrix does not have an inverse.
The given matrix M is a 1x2 matrix, so it's not square and it doesn't have an inverse.
Therefore, we can't find the inverse of matrix M.
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The volume of a gas 100mmHg pressure and at 40°C is 480mL. What volume does the gas occupy at standard temperature and pressure ?
Explanation:
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Answer:
The volume of the gas at standard temperature and pressure is 378 mL.
Step-by-step Explanation:
To solve this problem, we can use the combined gas law, which relates the pressure, volume, and temperature of a gas:
P1V1/T1 = P2V2/T2
where P1, V1, and T1 are the initial pressure, volume, and temperature, respectively, and P2, V2, and T2 are the final pressure, volume, and temperature, respectively.
We know that the gas has an initial pressure of 100 mmHg and an initial volume of 480 mL at a temperature of 40°C. We want to find the final volume of the gas at standard temperature and pressure, which is defined as 0°C and 1 atm (or 760 mmHg) of pressure.
First, we need to convert the initial temperature from Celsius to Kelvin by adding 273.15:
T1 = 40°C + 273.15 = 313.15 K
Next, we can plug in the values into the combined gas law equation:
(100 mmHg)(480 mL)/(313.15 K) = (760 mmHg)(V2)/(273.15 K)
We can solve for V2 by cross-multiplying and simplifying:
V2 = (100 mmHg)(480 mL)(273.15 K)/(313.15 K)(760 mmHg)
= 378 mL
Therefore, the volume of the gas at standard temperature and pressure is 378 mL.
metals that have luster are usually called as______
Answer:
lusterous metal
Explanation:
ex gold, iron etc hope it helps
how much molecules of sugar (sucrose) are in 4g of sugar?
Taking into account the definition of Avogadro's Number, 7.2276×10²¹ moles of sugar are in 4 g of sugar.
Definition of Avogadro's NumberAvogadro's number is the number of elementary entities (ie atoms, electrons, ions, molecules) that exist in one mole of any substance.
Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.
Definition of molar massThe molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, it is the amount of mass that a substance contains in one mole.
Number of molecules of sugarFirst, the molar mass of sugar is 342 g/mole and the following rule of three can be applied: If by definition of molar mass 342 g of sugar are contained in 1 mole, 4 g of sugar are contained in how many moles of the compound?
moles of sugar= (4 g of sugar× 1 mole)÷342 g of sugar
moles of sugar= 0.012 moles
Now you can apply the following rule of three: 1 mole of the compound contains 6.023×10²³ molecules, 0.012 mole of the compound contains how many molecules?
amount of molecules= (6.023×10²³ molecules × 0.012 mole)÷ 1 mole
amount of molecules= 7.2276×10²¹ moles
Finally, 7.2276×10²¹ moles of sugar are present.
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value: 4
Which of the following energy types are used in medical imaging process?
Light,heat,chemical, radiation
Answer:
radiation is the answer
The appearance of a gram-negative bacteria cell after the addition of the decolorizing agent (ethyl alcohol) in the Gram stain is _____.
(a) purple
(b) red
(c) colorless
(d) green.
Gram-negative bacteria appear as pink/red under the microscope after counterstaining with safranin. In conclusion, the appearance of a gram-negative bacteria cell after the addition of the decolorizing agent (ethyl alcohol) in the Gram stain is colorless.
The appearance of a gram-negative bacteria cell after the addition of the decolorizing agent (ethyl alcohol) in the Gram stain is colorless. Gram staining is a common microbiological method that is used to differentiate bacteria into two categories: Gram-positive and Gram-negative. This differentiation is based on differences in the composition of their cell walls. Gram staining is used to identify bacteria and fungi by staining the samples with crystal violet and iodine, then decolorizing with ethanol and counterstaining with safranin. This method helps to determine the presence or absence of a thick layer of peptidoglycan in the cell wall of bacteria. In Gram-negative bacteria, the decolorizing agent, ethyl alcohol, remove the outer membrane, causing the crystal violet stain to be removed from the cell wall, therefore resulting in a colorless appearance. The alcohol also increases the permeability of the thin peptidoglycan layer, which makes the safranin stain visible in the cell wall of the bacteria.
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what is the formula for co3+ and se2-?
The formula for Co3+ is Co3+ because it represents the ion of cobalt that has lost three electrons, leaving it with a 3+ charge.
What is chemical formula and how they are formed ?
A chemical formula is a symbolic representation of a chemical compound that shows the types of elements present in the compound and the relative number of atoms of each element. For example, the chemical formula for water is H2O, which indicates that it is made up of two hydrogen atoms and one oxygen atom.
Chemical formulas are formed by identifying the elements that make up a compound and determining the relative number of each element in the compound. The number of each element is represented by a subscript following the chemical symbol of the element. For example, the chemical formula for methane is CH4, which indicates that there is one carbon atom and four hydrogen atoms in each molecule of methane.
The formula for Se2- is Se2- because it represents the ion of selenium that has gained two electrons, giving it a 2- charge.
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Which value for Kc indicates an equilibrium that strongly favors reactants?
Select the correct answer below:
562
11.7
1.1
0.00496
0.00496 is the correct option for the equilibrium constant that strongly favors the reactants, according to the given problem.
Kc is the equilibrium constant for a reversible reaction. It is used to describe the equilibrium state of a chemical reaction. It is a constant value that indicates how much of a product will be produced at equilibrium for a given set of reactants. If Kc is larger than 1, the equilibrium will favor products. If Kc is less than 1, the equilibrium will favor reactants. So, the value for Kc that indicates an equilibrium that strongly favors reactants is 0.00496. When Kc is less than 1, the reaction equilibrium will be in favor of the reactants. If Kc is very small, it indicates that very little product is formed at equilibrium, implying that most of the reactants remain in equilibrium. A reaction that has a value of Kc less than 1 means that the forward reaction is less favored than the reverse reaction, indicating that the products will be less in quantity compared to the reactants. As a result, the equilibrium strongly favors the reactants.
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Reaction:
N2 + 3H2 ------> 2NH3
Question 1: Calculate the mass of N2 needed to react with 10 g of H2
Question 2: Calculate the mass of N2 needed to produce 15 g of NH3
Explanation:
The reactant contains 2N and 6H
The product contains 2N and 6H
Therefore, the chemical equation is balanced
From the equation, for every 1 mole of N2 that reacts, 3 moles of H2 are required.
We know 28.6 grams of N2 reacted, but we don’t know the mass ratio but just the mole ratio, so we have to convert 28.6 grams of N2 to the corresponding moles of N2.
From the periodic table, the molar mass of N is about 14 g/mol, so the molar mass of nitrogen gas or N2 is two times of that which is 28 g/mol.
With this, we can calculate moles of N2, but we also need to make sure the equation is setted up the right way.
Looking at the units, if we cancel out the grams, we are left with mol. We also know that in multiplication, numerator of one number cancel with the denominator of another number and vice versa
So the equation looks like this 28.6g * mol/28g = 1.021 mol N2
So the number of moles of H2 required is 1.021 mol N2 * 3 mol H2/1 mol N2 = 3.063 mol H2 (notice that mol N2 canceled out, so the equation is set up correctly)
However, the question ask for number of grams of H2 needed, so we need the molar mass of hydrogen gas or H2, which is 1*2 = 2 g/mol
3.063 mol H2 * 2 g H2/ mol H2 = 6.126 g H2
Ans: 6.126 g H2
For the partially completed Lewis structures, pick the correct Lewis structure.
How many Valence Electrons total overall?
The correct Lewis structures of the compounds that we have in the question have been shown in the images attached.
What is the Lewis structure?A Lewis structure is a diagram that shows the bonding between atoms in a molecule and the arrangement of electrons around the atoms. It is also known as a Lewis dot structure, Lewis dot diagram, or electron dot structure.
Lewis structures are useful in predicting the geometry of molecules and determining the polarity of molecules. They are also helpful in understanding the reactivity of molecules and how they interact with other molecules.
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A chemist prepares a solution of potassium permanganate (KMnO4) by measuring out 36. mol of potassium permanganate into a 500. mL volumetric flask
and filling the flask to the mark with water.
Calculate the concentration in mol/L of the chemist's potassium permanganate solution. Be sure your answer has the correct number of significant digits.
The concentration of the potassium permanganate solution is 72 mol/L. The answer has three significant figures because the volume of the flask has only one significant figure.
How The answer was obtainedThe concentration of the potassium permanganate solution can be calculated using the formula:
concentration = moles of solute / volume of solution
where the volume of solution is in liters.
First, we need to convert the volume of the flask from milliliters to liters:
500 mL = 0.500 L
Next, we can calculate the concentration of the solution:
concentration = 36. mol / 0.500 L
concentration = 72 mol/L
The concentration of the potassium permanganate solution is 72 mol/L. The answer has three significant figures because the volume of the flask has only one significant figure.
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which the following optically active alcohol is treated with hbr, a racemic mixture of alkyl bromides is obtained
(S)-2-butanol will undergo an SN2 reaction with HBr to produce a racemic mixture of alkyl bromides. Here option B is the correct answer.
When optically active alcohol is treated with HBr, the reaction follows an SN1 or SN2 mechanism. In the case of SN1, a carbocation intermediate is formed, and in SN2, a backside attack by the nucleophile occurs. The stereochemistry of the product depends on the configuration of the intermediate and the direction of attack.
In the case of (S)-2-butanol, the hydroxyl group is attached to the second carbon atom, which makes it a primary alcohol. When treated with HBr, it undergoes an SN2 reaction, where the hydroxyl group is replaced by the bromine atom. The nucleophile attacks from the backside of the molecule, leading to an inversion of configuration.
This results in the formation of a racemic mixture of alkyl bromides, as both enantiomers have an equal chance of being attacked from either side. On the other hand, (R)-2-butanol, being the enantiomer of (S)-2-butanol, will also undergo the same reaction and produce the same racemic mixture of alkyl bromides.
In the case of (R)-1-phenyl ethanol and (S)-1-phenyl ethanol, they are secondary alcohols and can undergo either SN1 or SN2 reactions depending on the reaction conditions. However, the reaction mechanism will lead to the formation of a mixture of diastereomers, rather than a racemic mixture of enantiomers.
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Complete question:
Which of the following optically active alcohols, when treated with HBr, results in a racemic mixture of alkyl bromides?
a) (R)-2-butanol
b) (S)-2-butanol
c) (R)-1-phenyl ethanol
d) (S)-1-phenyl ethanol