AnswersAA-F26 Physical ScienceBalancing Chemical Equations

Balancing Chemical Equations Answers

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The equations are not balanced. Which equation would have the same coefficients in the same order as 2CO2 + 3H20 C2H6O + 3O2?

Question illustration
A
FeCl3 + NH4OH Fe(OH)3 + NH4Cl
Option A
B
CH4 + O2 CO2 + H2O
Option B
C
Fe + H2SO4 Fe2(SO4)3 + H2
Option C
D
PCl5 + H2O HCl + H3PO4
Option D
3

Kiley wants to balance the equation H2 + N2 → NH3. Which would be her first step in balancing an equation?

A
multiplying the subscripts in the atoms of the reactants together
B
adding the coefficient 3 in front of H2 and the coefficient 2 in front of NH3
C
changing the subscripts so they match for the total number of atoms
D
creating a chart that shows the number of atoms in the reactants and products
4

Which is the balanced equation for V2O5 + CaS → CaO + V2S5?

A
V2O5 + CaS → CaO + V2S5
B
5V2O5 + 5CaS → 10CaO + 5V2S5
C
3V2O5 + 3CaS → 3CaO + 3V2S5
D
V2O5 + 5CaS → 5CaO + V2S5
5

The amount of oxygen in the reactants is 4 atoms. In the products, the oxygen is distributed to water (H2O) and O2 gas. Which coefficients would be placed in front of water and oxygen?

A
2 in front of water and 2 in front of oxygen
B
1 in front of water and 2 in front of oxygen
C
1 in front of water and 1 in front of oxygen
D
2 in front of water and 1 in front of oxygen
7

Plants use sunlight as energy to convert carbon dioxide and water into glucose and oxygen. Which best describes the reaction?

A
The law of conservation of mass indicates the same amount of carbon will be found in the reactants as in the products.
B
The law of conservation of energy indicates the same amount of carbon will be found in the reactants as in the products.
C
The law of conservation of mass indicates the same amount of glucose will be found in the reactants as in the products.
D
The law of conservation of energy indicates the same amount of glucose will be found in the reactants as in the products.
8

Which best describes the law of conservation of mass?

A
The coefficients in front of the chemicals in the reactants should be based on the physical state of the products.
B
Products in the form of gases are not considered a part of the total mass change from reactants to products.
C
When reactants contain both a solid and a liquid, the solid counts toward the overall mass and the liquid does not.
D
The mass of the reactants and products is equal and is not dependent on the physical state of the substances.
9

Lana balanced an equation so that the result was 2C2H3Br + 5O2 → 4CO2 + 2H2O + 2HBr. Which most likely represents the starting equation?

A
2C4H3Br + 5O2 → 4CO2 + 2H2O + 2HBr
B
C2H3Br + 5O2 → 4CO2 + H2O + 2HBr
C
C4H3Br + O2 → CO2 + H2O + HBr
D
C2H3Br + O2 → CO2 + H2O + HBr
11

Akia is balancing the equation Na + H2O NaOH + H2. He tries to find the coefficients that will balance the equation.How could he find the correct coefficients?

Question illustration
A
by counting each individual atom and making sure the number of each kind of atom is the same in the reactants and the products
B
by counting the total atoms and making sure the number of atoms in the reactants is the same as the number of atoms in the products
C
by counting the total mass of each compound and making sure the reactants have more mass than the products
D
by counting the mass of each atom and making sure the reactants are more massive than the products
12

One half of a balanced chemical equation is shown.3Mg(OH)2 + 2H3PO4Which lists the numbers of each atom the other half of the equation would contain?

A
3 Mg, 2 P, 14 O, 12 H
B
Mg, 2 P, 14 O, 6 H
C
3 Mg, 8 P, 7 O, 6 H
D
6 Mg, 6 P, 2 O, 12 H
13

The equation below shows a general equation for a reaction, and the amounts of the substance are written underneath. AB + CD → AC + BD(15 g) (?) (?) (10 g)The total mass of the products is 50g. Which best completes the other two amounts?

A
The amount of CD is 40 g, and the amount of AC is 35 g.
B
The amount of CD is 35 g, and the amount of AC is 40 g.
C
The amount of CD and AC would be the same.
D
The amount of CD and AC is undetermined.
14

The equations are not balanced. Which equation would have the same coefficients in the same order as 2CO2 + 3H20 C2H6O + 3O2?

Question illustration
A
FeCl3 + NH4OH Fe(OH)3 + NH4Cl
Option A
B
CH4 + O2 CO2 + H2O
Option B
C
Fe + H2SO4 Fe2(SO4)3 + H2
Option C
D
PCl5 + H2O HCl + H3PO4
Option D
15

Substances A and B react in a ratio of A + B → AB. Colin was combining substance A and substance B to form substance AB. He added 10 g of substance A and 45 g of substance B.

A
10 g
B
35 g
C
45 g
D
55 g
16

Charlie is balancing an equation. She has identified the atoms and counted the number of each in the reactants and products. What would Charlie adjust to make the number of atoms in the reactants the same as the number of atoms in the products?

A
coefficients
B
subscripts
C
superscripts
D
parentheses
17

Which equation is balanced?

A
Mg3N2 + H2O 3MgO + 2NH3
Option A
B
C3H8 + 5O2 H2O + 3CO2
Option B
C
Zn + 2HCl ZnCl2 + H2
Option C
D
3H2SO4 + 2Fe Fe2(SO4)3 + H2
Option D
18

The equation below is for potassium oxide. 4K + O2 2K2O What is the ratio of atoms of potassium to atoms of oxygen?

Question illustration
A
1:2
B
2:1
C
4:1
D
1:4
19

Which property of matter is conserved in chemical reactions and shown by balanced equations?

A
mass
B
volume
C
density
D
shape

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