Answer:
Q = 32,007.6 J
Explanation:
Hello there!
In this case, since the energy involved during a heating/cooling process is:
[tex]Q=mC(T_f-T_i)[/tex]
Thus, given the mass, specific heat of water, initial temperature and final one, we plug in obtain:
[tex]Q=450g*4.184\frac{J}{g\°C} (37.0\°C-20.0\°C)\\\\Q=32,007.6J[/tex]
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A piece of string is found to be 35.9 meters long. How long is the string in inches?
Answer: 1413.39 inches
Explanation:
Formula for converting meters to inches
Meters x 39.37 (roughly) = Value in inches
Applying formula
35.9 meters x 39.37 = 1413.39 inches (roughly)
Which of the following aqueous solutions are good buffer systems?
(Select all that apply.)
a. 0.28 M hydrobromic acid + 0.24 M sodium bromide
b. 0.29 M ammonia + 0.38 M ammonium bromide
c. 0.22 M hypochlorous acid + 0.18 M hydroiodic acid
d. 0.37 M sodium chloride + 0.25 M barium chloride
e. 0.13 M sodium hydroxide + 0.28 M sodium bromide
0.29 M ammonia + 0.38 M ammonium bromide and 0.22 M hypochlorous acid + 0.18 M hydroiodic acids of aqueous solutions are good buffer systems.
Buffer Systems:A solution that resists pH change when acids or bases are added to it is referred to as a buffer system. Either a weak acid and its salt, or a weak base and its salt, make up buffer systems. The ratio of HX/X- does not considerably alter when an acid or a base is introduced to a buffer.
Solutions known as buffers withstand pH changes when an acid or base is added. A weak base (A) and its conjugate weak acid (HA) are both present in buffers. When a reactive system is in equilibrium, adding a strong electrolyte with one common ion will cause the equilibrium to shift, lowering the concentration of the common ion. Buffers differ from one another in terms of pH range and buffer capacity.
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An acid-base indicatior is a compound who's color is pH dependent. That is, it changes color depending upon whether it is in acid or base. This is because indicators are weak acids and undergo the following equilibrium. H-Ind ↔ H+1 + Ind-1 H-Ind = the indicator molecule that is protonated and predominates under acidic conditions. Ind-1 = the deprotonated indicator molecule (the conjugate base of the acid) and predominates under basic conditions. We are using the Acid-Base indicator, phenopthalein for this experiment. What is the color of this indicator in Acid? . What is the color of this indicator in Base
Phenolphthalein is pink in acid and colorles in base.
Substances called indicators are those whose solutions change colour as the pH changes. We refer to these as acid-base indicators. The conjugate base or acid versions of these typically weak acids or bases have various hues because of variations in their absorption spectra. When it comes into contact with an object that has a pH of 8.2, it turns pink. At a pH higher than that, it turns purple.
Additionally, ionisation, which modifies the charge and structure of the phenolphthalein molecule, is the cause of this shift in colour. If it comes into contact with an acid like vinegar or a neutral substance like water, it retains its colorlessness.
Therefore, Phenolphthalein is pink in acid and colorles in base.
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What is the molality of lithium ions in a 0.302 m solution of Li₃PO₄ assuming the compound dissociates completely?
The molality of the lithium ions is calculated as 0.906 m
What is the molality of lithium ions?Given that the compound is written as Li₃PO₄, the dissociation of the compound is given by the equation;
Li₃PO₄ -----> 3Li^+ + PO₄^3-
Since there are three mole of lithium ions in the compound, it the follows that the molality of the lithium ions is;
3 * 0.302 m = 0.906 m
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The heat from the bonfire is transferred to the student's hands through the process of
conduction
convection
radiation
reflection
Answer:
Radiation
Explanation:
An object weighs 32 newtons. What is its mass if a gravitometer indicates that g = 8.25 m/sec2?
Answer:
3.88kg
Explanation:
weight=mass_of_body(m) x acceleration_due_to_gravity(g)
The weight is given and acceleration is also give
For mass divide the weight by acceleration.
Determine the moles of solute in a 350g solution that is 2.5 molal.
Answer:
0.875 moles solute
Explanation:
You can find the moles of the solute using the molality ratio:
Molality = moles solute / mass (kg) solution
After converting the mass to kilograms, you can plug the values into the ratio and simplify to find the moles.
1,000 g = 1 kg
350 g 1 kg
-------------- x --------------- = 0.35 kg solution
1,000 g
Molality = moles solute / mass solution
2.5 m = moles solute / 0.35 kg
0.875 = moles solute
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Radium-223 nuclei usually decay by alpha emission. Once in every billion decays, a radium-223 nucleus emits a carbon-14 nucleus.
Write a balanced nuclear equation for carbon-14 emission.
The equation for carbon-14 emission by Radium-223 nuclei is given below:
[tex]^{223}_{88}Ra \rightarrow\: ^{209}_{82}Pb + \:^{14}_{6}C[/tex]
What is radioactivity?Radioactivity is the spontaneous decay of a substance with emission of radiation.
The equation for carbon-14 emission by Radium-223 nuclei is given below:
[tex]^{223}_{88}Ra \rightarrow\: ^{209}_{82}Pb + \:^{14}_{6}C[/tex]
In conclusion, the emission of carbon-14 by Radium-223 nuclei produces Lead-209 nuclei.
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Why does Paul Ehrlich concede that the theory of evolution “cannot be refuted by any possible observations” and thus is “outside of empirical science”?
Evolution can not be tested by experiment given that it depends largely on observations that fit into a wider scope and point to a common conclusion.
Can evolution be proven empirically?Science is know to be empirical, In science, the evidence that backs up a claim is what establishes it as true or false. Thus all theories must be tested by experiment.
However, the theory of evolution can not be tested by experiment given that it depends largely on observations that fit into a wider scope and point to a common conclusion. In other words, evolution lies “outside of empirical science”.
The fact that it can not be directly proven empirically does not necessarily make it out to be false. That was the conclusion of Paul Ehrlich in his 1967 article.
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What are the molecular polarity and the intermolecular forces present in the sun
The molecular polarity of the sun is the dipoole separation of electric charge leading to a molecule in the sun.
What is molecular polarity?Molecular polarity simply refers to those regions of molecules containing or possessing positive and negative charge
So therefore, the molecular polarity of the sun is the separation of electric charge leading to a molecule in the sun.
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What mass of water was produced if 350.0 L of carbon dioxide were made at STP? C3H8 (g) + 5O2(g) → 2CO2 (g) + 4H2O (g)
700 L of water was produced if 350.0 L of carbon dioxide were made at STP.
The quantitative relationship (ratio) between reactants and products in a chemical reaction that produces gases is known as gas stoichiometry. When the created gases are presumed to be ideal and their temperature, pressure, and volume are all known, gas stoichiometry is applicable.
The ideal gas equation is PV=nRT, where n is the number of moles and R is the gas constant, P is the pressure measured in atmospheres (atm), V is the volume measured in liters (L), and
Calculations based on stoichiometry assist scientists and engineers who work in the business world in estimating the number of items they will make using a particular process. They can also assist in determining if a product will be economical to produce.
Reduced growth, reproduction, and survivability for the consumer are typically the results of a significant stoichiometric imbalance between the primary producer and consumer.
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Students in a chemistry lab are making the compound cobalt(II) carbonate.
It can be made by reacting sodium carbonate solution with cobalt(II) chloride solution. Calculate the volume of 2.0 mol/L cobalt(II) chloride solution required to completely react with 250 mL of 1.5 mol/L sodium carbonate.
The volume of 2.0 mol/L cobalt(II) chloride solution required for the reaction is 187.5 mL
How to determine the mole of Na₂CO₃ in the solutionVolume of Na₂CO₃ = 250 mL = 250 / 1000 = 0.25 LMolarity of Na₂CO₃ = 1.5 mol/LMole of Na₂CO₃ = ?Mole = molarity × volume
Mole of Na₂CO₃ = 1.5 × 0.25
Mole of Na₂CO₃ = 0.375 mole
How to determine the mole of CoCl₂ neededBalanced equation
CoCl₂ + Na₂CO₃ -> CoCO₃ + 2NaCl
From the balanced equation above,
1 mole of Na₂CO₃ reacted with 1 mole of CoCl₂.
Therefore,
0.375 mole of Na₂CO₃ will also react with 0.375 mole of CoCl₂.
How to determine the volume of CoCl₂Molarity of CoCl₂ = 2 mol/LMole of CoCl₂ = 0.375 moleVolume of CoCl₂ = ?Volume = mole / molarity
Volume of CoCl₂ = 0.375 / 2
Volume of CoCl₂ = 0.1875 L
Multiply by 1000 to express in mL
Volume of CoCl₂ = 0.1875 × 1000
Volume of CoCl₂ = 187.5 mL
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What volume of 0.555M KNO3 solution would contain 12.5 g of solute
The volume of 0.555M KNO3 solution would contain 12.5 g of solute iss 223 mL.
What is the relationship between mass of solute and concentration of solution?The mass of solute in a given volume of solution is related by the formula below:
Molarity = mass/(molar mass * volume)Therefore, volume of solution is given by:
Volume = Mass /molarity * molar mass
Molar mass of KNO₃ = 101 g/mol
Volume = 12.5/(0.555 * 101)
Volume = 0.223 L or 223 mL
In conclusion, the volume of the solution is obtained from the molarity of solution as well as mass and molar mass of solute.
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Calculate the volume of 32% HCl required to make about 1 N HCl in 100ml volumetric flask
9.82 mL is the volume of 32% HCl required to make about 1 N HCl in 100ml volumetric flask.
What is Law of Equivalent ?N₁V₁ = N₂V₂
where,
N₁ = Normality of solution with known concentration
V₁ = Volume of solution with known concentration
N₂ = Normality of solution with unknown concentration
V₂ = Volume of solution with unknown concentration
Now find the mass of solution
Mass = Density × Volume
= 1.16 × 0.32 × 1000
= 371.52 g
How to find the Normality ?Normality = [tex]\frac{\text{Weight}}{\text{Equivalent weight}}[/tex]
= [tex]\frac{371.52\ g}{36.5}[/tex]
= 10.18 equivalents
Now put the values in above formula we get
N₁V₁ = N₂V₂
1 × 100 = 10.18 × V₂
100 = 10.18 × V₂
[tex]V_{2} = \frac{100}{10.18}[/tex]
= 9.82 mL
Thus from the above conclusion we can say that 9.82 mL is the volume of 32% HCl required to make about 1 N HCl in 100ml volumetric flask.
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Balance the equation below and identify the type.
NH4NO₂(s)---> N₂(g) + H₂O(l)
Consider the reaction of NaHCO3
with an acid, HA. How many grams of NaHCO3
are required to produce 1.76 g of CO2?
The mass of NaHCO₃ required to produce 1.76 g of CO₂ is 3.36 g
Balanced equationNaHCO₃ + HA --> NaA + CO₂ + H₂O
Molar mass of NaHCO₃ = 84 g/mol
Mass of NaHCO₃ from the balanced equation = 1 × 84 = 84 g
Molar mass of CO₂ = 44 g/mol
Mass of CO₂ from the balanced equation = 1 × 44 = 44 g
SUMMARY
From the balanced equation above,
44 g of CO₂ were produced from 84 g of NaHCO₃
How to determine the mass of NaHCO₃ neededFrom the balanced equation above,
44 g of CO₂ were produced from 84 g of NaHCO₃
Therefore,
1.76 g of CO₂ will be produced from = (1.76 × 84) / 44 = 3.36 g of NaHCO₃
Thus, 3.36 g of NaHCO₃ is needed for the reaction
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How many MOLES of sulfur hexafluoride are present in 2.33x1022 molecules of this compound
Answer:
0.0387 moles SF₆
Explanation:
To find the moles of sulfur hexafluoride (SF₆), you need to multiply the number of molecules by Avogadro's number. Avogadro's number is a ratio between molecules and moles. It is important to arrange the conversion in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 3 sig figs to match the sig figs of the given value (2.33 x 10²²).
Avogadro's Number:
6.022 x 10²³ molecules = 1 mole
2.33 x 10²² molecules SF₆ 1 mole
--------------------------------------- x ------------------------------------ = 0.0387 moles SF₆
6.022 x 10²³ molecules
Suppose certain sample takes 100 min for 750 mL water to percolate into the
soil. Calculate the rate of percolation of water.
The rate of percolation of water into the soil will be 0.125 mL per second
Percolation rateThe rate of percolation of water into the soil is determined by the volume of water that enters the soil per unit of time under specific conditions.
In this case, 750 mL of water percolated in 100 minutes.
100 minutes = 100 x 60 = 6,000 seconds
Percolation rate = 750/6000 = 0.125 mL per second
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How many grams of calcium are in 2.25 molar of calcium
Answer:
40 g
Explanation:b
To answer this question, you may need access to the periodic table of elements.
Which of these would likely be the best conductor of electricity?
a.) H₂
b.) NO₂
c.) CaCl₂
d.) H₂O
Answer:
A
Explanation:
Beacuse the hydrogen is best
The best conductor of electricity here is calcium chloride because, metals are good conductors by the presence of free electrons. The CaCl₂ solution ionizes to Ca²⁺ ions and Cl- ions make it a good electrolyte.
What is conductivity?Conductivity is a physical property which describes the ability of a substance to pass electricity through it. The substance which shows good conductivity at normal temperatures are called conductors and those only conducts at higher temperatures are semiconductors.
Substance which does not conduct in any condition are called insulators. Metals are electron rich and the metal crystal lattice is composed of a sea of mobile electrons and a pool of positive ions. The delocalization of electrons make it easy to pass current through it.
When a metallic solution is ionized, it gives free ions and electrons and make the solution conducting. CaCl₂ is a good conductor since it contains the metal ions Ca²⁺ . Hence, option c is correct.
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Which of these accurately describes a difference between nuclear energy and
Fossil fuel?
A. In nuclear fuel reactions, heat is released that is used to do work.
B. In fossil fuel reactions, heat is released that is used to do work.
C. Fossil fuels have a higher energy density than nuclear fuel.
D. Nuclear fuel has a higher energy density than fossil fuels.
Answer:
Nuclear fuel has a higher energy density than fossil fuel
I need help with my work
By the mean value theorem, the function y = sin x² on the interval [0, π/4] has this guaranteed number: x ≈ 0.460.
How to find a number that guarantees the mean value theorem
According to the mean value theorem, a function that is differentiable at an interval [a, b] has a number c within the interval such that:
f'(c) = [f(b) - f(a)]/(b - a) (1)
The first derivative of the function is f'(x) = 2 · x · cos x² and by the mean value theorem we know that:
2 · c · cos c² = [sin (π/4)²- sin 0²]/(π/4 - 0)
2 · c · cos c² = [- √2 / 2]/(π /4)
2 · c · cos c² ≈ 0.900
This equation cannot be solved analytically. By the resource of a graphing tool we found the following solution within the interval: c ≈ 0.460.
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Carbon monoxide and chlorine gas react to form phosgene:
If a reaction mixture initially contains 215 torr of CO and 245 torr of Cl2, what is the mole fraction of COCl2 when equilibrium is reached?
CO(g) + Cl2(g) ↔COCl2
KP= 310 atm at 700k
Carbon monoxide and chlorine gas react to form phosgene. If a reaction mixture initially contains 215 torr of CO and 245 torr of Cl₂. 0.76 is the mole fraction of COCl₂ when equilibrium is reached.
How to find Mole fraction ?CO(g) + Cl₂ (g) → COCl₂ (g) Kp = 310
With this reaction we can write the Kp expression
[tex]K_{p} = \frac{p_{COCl_2}}{p_{CO} \times p_{Cl_2}}[/tex]
We know that 1 atm = 760 torr
Now
[tex]p_{CO} = \frac{215 \times 1}{760}[/tex]
= 0.28 atm
[tex]p_{Cl_2} = \frac{245 \times 1}{760}[/tex]
= 0.32 atm
Now, we can write an ICE chart with pressures, so we can know the pressure of COCl₂.
CO(g) + Cl₂ (g) → COCl₂ (g) Kp = 310
I: 0.28 0.32 0
C: -x -x +x
E: 0.28 - x 0.32 - x x
Now put the value in Kp expression
[tex]K_{p} = \frac{p_{COCl_2}}{p_{CO} \times p_{Cl_2}}[/tex]
[tex]310 = \frac{x}{(0.28 - x) (0.32 - x)}[/tex]
[tex]310 = \frac{x}{0.0896 - 0.28x - 0.32x + x^2}[/tex]
310 (0.0896 - 0.28x - 0.32x + x²) = x
310 (0.0896 - 0.6 x + x²) = x
27.776 - 186 x + 310 x² = x
310 x² -187 x + 27.776 = 0
By using the quadratic equation find the value of x:
[tex]x = \frac{b \pm \sqrt{b^2 - 4ac}}{2a}[/tex]
[tex]= \frac{187 \pm \sqrt{(187)^2 - 4 \times 310 \times 27.776}}{2 \times 310}[/tex]
[tex]= \frac{187 \pm \sqrt{34969 - 34,442.24}}{620}[/tex]
[tex]= \frac{187 \pm \sqrt{526.76}}{620}[/tex]
[tex]= \frac{187 \pm 22.95}{620}[/tex]
[tex]= \frac{187 + 22.95}{620}\ \text{or}\ \frac{187 - 22.95}{620}[/tex]
[tex]= \frac{209.95}{620}\ \text{or}\ \frac{164.05}{620}[/tex]
[tex]= 0.33\ \text{or}\ 0.26[/tex]
Using the lowest value of x, we have that the partial pressure of COCl₂ would be 0.26 atm.
PpCO = 0.28 - x = 0.28 - 0.26 = 0.02
PpCl₂ = 0.32 - x = 0.32 - 0.26 = 0.06
[tex]X_{COCl_2} = \frac{P_{COCl_2}}{Pt}[/tex]
And Pt is the total pressure of all species in reaction so:
Pt = 0.02 + 0.06 + 0.26 =
= 0.34 atm
The mole fraction:
[tex]X_{COCl_2} = \frac{0.26}{0.34}[/tex]
= 0.76
Thus from the above conclusion we can say that Carbon monoxide and chlorine gas react to form phosgene. If a reaction mixture initially contains 215 torr of CO and 245 torr of Cl₂. 0.76 is the mole fraction of COCl₂ when equilibrium is reached.
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Write an equation for the neutralization of lemon juice with baking soda. Your equation should show a proton transfer to form carbonic acid and a salt.
The equation of the neutralization reaction is:
HOC(CO₂H)(CH₂CO₂H)₂ + Na₂CO₃ ----> HOC(CO₂Na)(CH₂CO₂Na)₂ + H₂O
What is the acid in lemon juice?The main acid in lemon juice is citric acid.
Citric acid is a tricarboxylic acid and will react with baking soda to form a salt and water.
The equation of the neutralization reaction is shown below:
HOC(CO₂H)(CH₂CO₂H)₂ + Na₂CO₃ ----> HOC(CO₂Na)(CH₂CO₂Na)₂ + H₂O
In conclusion, the neutralization of citric acid in lemon juice produces a salt and water.
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7. Which of the following compound is the most soluble in CC14? C. NH3 A. HF B. NaCl D. C10H22
C10H22 is a compound which is the most soluble in CC14 because both are non-polar in nature.
Why polar solute soluble in polar solvent?We know that like dissolve like which means that polar solutes only dissolve in polar solvent while on the other hand, non-polar solutes only dissolve in non-polar solvent.
So we can conclude that C10H22 is a compound which is the most soluble in CC14 because both are non-polar in nature.
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Calculate the following using proper units and significant figures: (5.57 m / 0.63 m) - (1.11 m x 0.82 m)
7.93 m
7.931 m
7.9 m²
7.9311 m²
This will give the value of 7.9311m2
( 5.57m / 0.63m ) - ( 1.11m * 0.82m )
= 8.8413 - ( 1.11m * 0.82m )
= 8.8413 - 0.9102m2
= 7.9311m2
Dividing a value in meter by another value in meter results in the cancellation of both the units and the resulting answer will have no unit.
Multiplying a value in meter by another value in meter it will result in the square meters. It can be written as m2 and can be read a meter square.
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The atom is sometimes said to be similar to a miniature planetary system, with electrons orbiting the nucleus. What does the uncertainty principle have to say about this view of the atom?
Answer:
The uncertainty principle says this view is only a guess, a snapshot of what the electrons around the nucleus could possibly look like. Specifically, the uncertainty principle says that we cannot know the exact location and speed of the electrons. Therefore, the planetary-like arrangement of the electrons around the nucleus is rarely ever assumed.
What is indicated by the methyl-prefix?
OA. The molecule is an alkene.
OB. The molecule is a branched hydrocarbon.
O C. The molecule is saturated with hydrogen atoms.
OD. The molecule is a stereoisomer.
Answer:
B.) The molecule is a branched hydrocarbon.
Explanation:
A hydrocarbon is any molecule made up of carbon and hydrogen exclusively. A methyl- prefix denotes the presence of a methyl group (CH₃), which is situated as a branch off of a hydrocarbon carbon.
Calculate the amount of heat deposited on the skin of a person burned by 1.00g of steam at 100.0C. Skin temperature is 37C. ΔHvap= 40.7kJ/mol.
The amount of heat deposited on the skin is 2.26 kJ.
What is the amount of heat given off by 1.0 g of steam?The amount of heat given off by steam is determined using the formula below:
Quantity of heat = mass * latent heat of vaporization.
Moles of steam = 1.0/18
Heat = 1.0/18 * 40.7
Heat deposited = 2.26 kJ
In conclusion, the quantity of heat is determined from the latent heat of vaporization and the moles of steam.
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C3H8O dissolved in water
If C3H8O is dissolved in water, it would be expected to be a strong electrolyte.
What is a strong electrolyte?
A strong electrolyte is a solute or solution (already an electrolyte) that can completely dissociates in solution.
C3H8O is one of those compounds expected to be a strong electrolyte.
Thus, if C3H8O is dissolved in water, it would be expected to be a strong electrolyte.
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