Answer:
what is represented is a substance
PbCl2(s) is a substance
When writing chemical formulae or equations , we use chemical symbols to express the state of matter and the conditions of an element, compound or reactants .
The symbols to represent physical states of matter are are
(s) This tells that the substance is in solid state
(aq ) means aqueous, It tells that the substance has been dissolved and it is in a solution.
(l)This tells that the substance is in liquid state
(g)This tells that the substance is in gaseos state
Now, PbCl2(s) is a substance in the solid state.
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La is element 57 on the periodic table a sample contains 2.82 * 10€25 power atoms of La calculate the amount of LA
Answer:
[tex]n=46.8molLa\\\\m=6.50x10^3gLa[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to calculate both moles and grams of lanthanum by using the Avogadro's number as a relationship of atoms to moles and its atomic mass as a relationship to moles to grams to obtain the following:
[tex]n=2.82x10^{25}atomsLa*\frac{1molLa}{6.022x10^{23}atomsLa}=46.8molLa\\\\m=46.8molLa*\frac{138.9gLa}{1molLa} =6.50x10^3gLa[/tex]
Regards!
Which equation represents a combustion reaction?
2SO2 + O2 → 2SO3
Pb(NO3)2 + 2HCl → PbCl2 + 2HNO3
2C2H6 + 7O2 → 4CO2 + 6H2O
Ca + 2HCl → CaCl2 + H2
Answer:
2SO2 + O2 => 2SO3
Explanation:
Combustion reaction involves heating of a compound/element/substance in presences of oxygen.
A length of copper wire has a mass of 6.19 g. How many moles of copper are in the wire? moles
Answer:
molar mass of copper = 63.55 g/mol
( 1 mol of copper)
6.19 g copper × ( 63.55g copper )
0.0975 moles
Determine whether or not each ion contributes to water hardness.
a. Ca2+
b. (HCO)3^-
c. K+
d. Mg2+
Answer: The ion that contribute to water hardness are:
--> a. Ca2+
--> b. (HCO)3^- and
--> c. Mg2+
While K+ DOES NOT contribute to water hardness.
Explanation:
WATER in chemistry is known as a universal solvent. This is so because it is polar in nature and dissolves most inorganic solutes and some polar organic solutes to form aqueous solutions. It is composed of elements such as hydrogen and oxygen in the combined ratio of 2:1.
Water is said to be HARD if it does not lather readily with soap. There are two types of water hardness:
--> Permanent hardness: This is mainly due to the presence of CALCIUM and MAGNESIUM ions in the form of soluble tetraoxosulphate(VI) and chlorides. These ions are removed by adding washing soda or caustic soda.
--> Temporary hardness: This is due to the presence of calcium HYDROGENTRIOXOCARBONATES. It can be removed by boiling and using slaked lime.
Therefore from the above given ions, Ca2+,(HCO)3^- and Mg2+ contributes to water hardness.
How many joules of heat energy are required to raise the temperature of 100.0 g of aluminum by 120.0°C? The specific heat of aluminum is 0.897 J/g.°C. 2 3
Answer:
10764 J
Explanation:
Remember the equation for specific heat::
q = mcΔT
q = 100 x 0.897 x 120
q = 10764
the intrument that tells both the speed and direction of the wind is the?
Answer:
anemometer
Explanation:
The instrument that is being described is called an anemometer. This is a device that has 4 ladel like objects that allow the wind to hit it, causing it to spin. The force of the spin allows meteorologists to calculate the speed of the wind. On top of this device is usually an arrow which can rotate around the device with the wind and point in the direction that the wind is blowing. Using a N, NE, E, SE, S, SW, W, and NW direction.
why is it preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride
Answer:
Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.
It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.
What is Dehydration ?A process such as a chemical reaction that removes water.The atoms which constitute the molecule of water that is removed.
Hence,It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent,
Thus, it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.
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Which of the following is true for a nuclear reaction? (5 points)
Select one:
a.Electrons are lost.
b.Electrons are gained.
c.The identity of element changes.
d.The identity of element remains same.
the identity of element remains same
How is the atomic mass of an element calculated?
Answer:
Mass number (A) is the number of nucleons (proton and neutron) present in a atom.
Explanation:
electrons don't cout since they are thousandth's of the mass of protons or neutrons
which effect of long-term environmental change is the driving force behind evolution?
Answer:
climate change
Explanation:
climate change is driving force of evolution because when the climate is changed the animal and human need to adapt to it's natural change.
10-Concentration is the amount of a substance in a predefined volume of space. The basic measurement of concentration in chemistry is molarity or the number of moles of solute per liter of solvent. What is the molarity of a solution containing 9.478 grams of Rucl, in enough water to make 1.00 L of solution?
Answer:
0.0457 M
Explanation:
Concentration is the amount of a substance in a predefined volume of space. The basic measurement of concentration in chemistry is molarity or the number of moles of solute per liter of solution. What is the molarity of a solution containing 9.478 grams of RuCl₃, in enough water to make 1.00 L of solution?
Step 1: Given data
Mass of RuCl₃ (solute): 9.478 gVolume of solution: 1.00 LStep 2: Calculate the moles corresponding to 9.478 g of RuCl₃
The molar mass of RuCl₃ is 207.4 g/mol.
9.478 g × 1 mol/207.4 g = 0.04570 mol
Step 3: Calculate the molarity of the solution
We will use the definition of molarity.
M = moles of solute / liters of solution
M = 0.04570 mol / 1.00 L = 0.0457 M
A certain alkyl halide is reacted with OH- to form an alcohol. The alkyl halide is optically active but the product(s) is/are optically inactive. Which of the following could be the reactant?a) 3-bromo-3-methylhexane.b) 1-chlorobutane.c) 2-bromo-2-methylbutane.d) 3-bromo-2,3,4-trimethypentane.
Answer:
a. 3-brumo - 3-methylhexane
Explanation:
Alkyl Halides can undergo substitution reactions. Nucleophiles are electron rich species and has negative charge while Electrophiles are electron deficient species which carry positive charge. Alkyl halide which have polar carbon atom are electrophiles.
For the iron thiocyanate system, what is the value of the equilibrium constant, Kc, if the following are the concentrations of all species present. Provide your answer to three digits after the decimal.
FeSCN2+ 0.501
Fe3+ 0.494
SCN- 0.639
Answer:
Kc = 0.630
Explanation:
The equilibrium of the thiocyanate system occurs as follows:
FeSCN²⁺(aq) ⇄ Fe³⁺(aq) + SCN⁻(aq)
And equilibrium constant, kc, is:
Kc = [SCN⁻] [Fe³⁺] / [FeSCN²⁺]
Replacing with the gven concentrations:
Kc = 0.639M*0.494M / 0.501M
Kc = 0.6305pts) Reaction Characterization (1pts) Select the type of reaction Choose... (1pts) Write the balanced equation for the formation of the Grignard reagent from bromobenzene. Include all reagents and products but not solvents.
Answer:
See explanation and image attached
Explanation:
Grignard reagent is any organic compound that is classified as an alkyl or aryl magnesium halide (RMgX).
Grignard reagents are produced when the alkyl halide reacts with magnesium metal in ether and tetrahydrofuran as solvents.
They are good nucleophiles and are involved in the synthetic routes to many important classes of organic compounds.
The formation of Grignard reagent from bromobenzene is shown in the image attached to this answer.
“Conductor, circuit breaker, switch” use the words provided to write the function of fuses.
Answer pls
Answer:
The fuse is a thin wire that is the conductor of electricity is designed to breaks the circuit if there is a fault in an appliance that causes excessive current to flow in a circuit.
The conductor used in the fuse is melt and separated in such cases of excessive current in a circuit and switch the current off.
A circuit breaker is made up of a thin wire that is specially designed to switch that automatically breaks circuit current in the overcurrent condition.
which chemical can be added to an acidic soil to make it neutral it's easy
Answer:
Boiled a added acidic solution for Lowe's home improvement for car insurance cost the Africa map of the soul
g A solution contains 100mM NaCl, 20mM CaCl2, and 20mM urea. We would say this solution is __________ compared to a 300 mOsM solution and ___________ compared to a cell with 300 mOsM (non-penetrating solutes) interior.
Answer:
A solution contains 100mM NaCl, 20mM CaCl2, and 20mM urea. We would say this solution is hypotonic compared to a 300 mOsM solution and hypotonic compared to a cell with 300 mOsM (non-penetrating solutes) interior.
Explanation:
The osmolarity is calculated from the molar concentration of the active particles in the solution. We have a solution that is composed of NaCl, CaCl₂ and urea.
When they are dissolved in water, they dissociate into particles as follows:
NaCl → Na⁺ + Cl⁻ (2 particles per compound)
CaCl₂ → Ca²⁺ + 2 Cl⁻ (3 particles per compound)
urea: not dissociation (1 particle per compound)
Then, we have to calculate the osmolarity of the solution. We multiply the molarity of each compound by the number of particles produced by the compound in water:
Osm = (100 mM NaCl x 2) + (20 mM CaCl₂ x 3) + (20 mM urea x 1) = 280 mOsm
Compared with 300 mOsm, 280 mOsm has a lower osmolarity, so it is a hypotonic solution.
To compare with a cell's osmolarity, we have to consider only the non-penetrating solutes. Urea is considered a penetrating solute for mammalian cells. So, the osmolarity of non-penetrating solutes (NaCl and CaCl₂) is calculated as:
Osm (non-penetrating solutes) = (100 mM NaCl x 2) + (20 mM CaCl₂ x 3) = 260 mOsm
Therefore, we have:
Compared to 300 mOsm solution ⇒ 280 mOsm solution is a hypotonic solution
Compared to a cell with 300 mOsm ⇒ 260 mOsm solution is hypotonic
A certain liquid has a normal freezing point of and a freezing point depression constant . Calculate the freezing point of a solution made of of iron(III) chloride () dissolved in of . Round your answer to significant digits.
The question is incomplete, the complete question is:
A certain liquid X has a normal freezing point of [tex]0.80^oC[/tex] and a freezing point depression constant [tex]K_f=7.82^oC.kg/mol[/tex] . Calculate the freezing point of a solution made of 81.1 g of iron(III) chloride () dissolved in 850. g of X. Round your answer to significant digits.
Answer: The freezing point of the solution is [tex]-17.6^oC[/tex]
Explanation:
Depression in the freezing point is defined as the difference between the freezing point of the pure solvent and the freezing point of the solution.
The expression for the calculation of depression in freezing point is:
[tex]\text{Freezing point of pure solvent}-\text{freezing point of solution}=i\times K_f\times m[/tex]
OR
[tex]\text{Freezing point of pure solvent}-\text{Freezing point of solution}=i\times K_f\times \frac{m_{solute}\times 1000}{M_{solute}\times w_{solvent}\text{(in g)}}[/tex] ......(1)
where,
Freezing point of pure solvent = [tex]0.80^oC[/tex]
Freezing point of solution = [tex]?^oC[/tex]
i = Vant Hoff factor = 4 (for iron (III) chloride as 4 ions are produced in the reaction)
[tex]K_f[/tex] = freezing point depression constant = [tex]7.82^oC/m[/tex]
[tex]m_{solute}[/tex] = Given mass of solute (iron (III) chloride) = 81.1 g
[tex]M_{solute}[/tex] = Molar mass of solute (iron (III) chloride) = 162.2 g/mol
[tex]w_{solvent}[/tex] = Mass of solvent (X) = 850. g
Putting values in equation 1, we get:
[tex]0.8-(\text{Freezing point of solution})=4\times 7.82\times \frac{81.1\times 1000}{162.2\times 850}\\\\\text{Freezing point of solution}=[0.8-18.4]^oC\\\\\text{Freezing point of solution}=-17.6^oC[/tex]
Hence, the freezing point of the solution is [tex]-17.6^oC[/tex]
..............................................................................................
The main product of free radical bromination of methane is
A) ethane
B) chloromethane
C) bromonethane
D) bromine
Answer: C
Explanation:
what is the atomic structure of an element that has atomic number of 11 and neutron number of 12.
Answer:
See explanation
Explanation:
The atomic number refers to the number of protons in the nucleus, it also tells us the number of electrons in the neutral atom since the atom is electrically neutral because the number of protons and electrons are equal.
If an atom has the atomic number 11, then the electrons in the atom are arranged in the shells in the order; 2, 8, 1.
Two electrons are found in the innermost shell, eight electrons are found in the next shell and one electron is found on the outermost shell.
The nucleus of the atom is composed of a total of 23 nucleons; 11 protons and 12 neutrons.
Question 10 What is the UPAC name for this compound? CH3-----CHO
Answer:
Ethanal or acetaldehyde
Explanation:
Ethanal, also called acetaldehyde is the second member of the alkanal or aldehyde group of hydrocarbons, which have a functional group of -CHO. The -CHO functional group characterizes every member to this group and makes them behave chemically similar.
However, the second member of this aldehyde group with a formula of CH3----CHO, has a methyl group (CH3) attached to the functional group, hence, it is called ETHANAL OR ACETALDEHYDE.
Which statement shows why mass is conserved for this reaction? 2Mg + O2 → 2MgO
Answer:
The same number of each atom are on both sides of the equation.
The Law of conservation of mass states that matter is neither destroyed nor created in a chemical reaction. Therefore, the mass of the reactants will be equal to the mass of the products in a chemical reaction. According to the law matter is neither created nor destroyed in a chemical reaction.
What is the name of the functional group that is made of a carbon atom
double bonded to an oxygen atom?
O A. Carbonyl
O B. Ether
O c. Alcohol
O D. Ester
Help on both please and thanks
Answer:
1. Granite
2. 535.5J
Explanation:
1. The lower the specific heat capacity of a substance, which is the amount of heat needed to raise the temperature of a particular mass of substance by 1 °C or K, the slower the rate at which the temperature is raised.
In this question 1, the substance with the lowest specific heat capacity in J/gK is GRANITE, hence, it will raise temperature the slowest.
2. Using the formula as follows:
Q = m × c × ∆T
Where;
c = specific heat capacity
Q = amount of heat (J)
m = mass of substance
∆T = change in temperature (°C)
m = 35g, c = 0.45 J/g°C, ∆T = 54°C - 20°C = 34°C
Q = 35 × 0.45 × 34
Q = 535.5J
phương pháp VI PHÂN ĐỒ THỊ để xác định bậc phản ứng
Answer:
mwlooy kagabi jal
64 JAHA VI PHÂN KAY
Soybeans is used in food production and cooking in 2007 United States produced 3.06 billions bushels of soybeans and 65% of the harvest was used to make soybeans oil
Answer:
1.071
Explanation:
Answer:
Find the percentage of soybeans used for other purposes:
100% − 65% = 35%.
Multiply the result (35%) by the total bushels of soybeans produced:
35
100
=
0.35
.
0.35 × 3.06 billion bushels = 1.071 billion bushels
The amount of soybeans used for other purposes was 1.071 billion bushels.
Explanation:
PLATO
What size volumetric flask would you use to create a 1.00M solution using 166.00 g of KI?
Answer:
A 1 liter volumetric flask should be used.
Explanation:
First we convert 166.00 g of KI into moles, using its molar mass:
Molar mass of KI = Molar mass of K + Molar mass of I = 166 g/mol
166.00 g ÷ 166 g/mol = 1 mol KIThen we calculate the required volume, using the definition of molarity:
Molarity = moles / litersLiters = moles / molarity
1 mol / 1.00 M = 1 LGive the IUPAC name for the following alkyl group, and classify it as primary, secondary, or tertiary.
CH3(CH2)9CH2
Answer:
Give the IUPAC name for the following alkyl group, and classify it as primary, secondary, or tertiary.
CH3(CH2)9CH2
Explanation:
In the given alkyl group there are eleven carbon atoms.
So, the alkyl group name is:
n-undecyl.
Pimary carbon is the one which is attached only one other carbon atom,group.
Secondary carbon is the one which is attached to two carbons.
Thertiary carbon is the one which is attached to three other carbons.
In the given alkyl group,
the primary,secondary alkyl groups are shown below:
There is no tertiary carbon atom in the given molecule.
Which of the following is NOT likely to cause a change in average annual temperatures on Earth?
a. Human activity. b. Solar eclipses.
c. Photosynthesis by plants and algae. d. Strength of solar radiation.
Answer:
i think C is the answer
Explanation:
The change in average annual temperatures on earth will be due to "photosynthesis by plants and algae".
What is photosynthesis?Photosynthesis can be defined as a process in which plants, as well as other organisms, as well as other organisms, utilize to transform sunlight into chemical energy which can then be released to power the organism's activities using cellular respiration.
What is plants?
Plants seem to be mostly photosynthetic eukaryotes belonging to the plantae kingdom.
Therefore, photosynthesis cannot change in average annual temperature on Earth.
To know more about photosynthesis.
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