Conservation in Chemical Reactions Quick Check
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Question
In which chemical equation is the number of atoms in the reactants the same as the number of atoms in the products?(1 point)
Responses
CH4 + O2 → CO2 + 2H2O
CH 4 + O 2 → CO 2 + 2H 2 O
CO2 + H2O → CH2OH + O2
CO 2 + H 2 O → CH 2 OH + O 2
Li2CO3 → LiO + CO2
Li 2 CO 3 → LiO + CO 2
Zn + 2HCl → H2 + ZnCl2
Zn + 2HCl → H 2 + ZnCl 2
Zn + 2HCl → H2 + ZnCl2
Conservation in Chemical Reactions Quick Check
2 of 42 of 4 Items
Question
Which statement is true regarding a chemical reaction?(1 point)
Responses
The total number of atoms changes, so mass is conserved in the reaction.
The total number of atoms changes, so mass is conserved in the reaction.
The total number of atoms does not change, so mass is conserved in the reaction.
The total number of atoms does not change, so mass is conserved in the reaction.
Even if the total number of atoms changes, mass may not be conserved in the reaction.
Even if the total number of atoms changes, mass may not be conserved in the reaction.
Even if the total number of atoms does not change, mass may not be conserved in the reaction.
The total number of atoms does not change, so mass is conserved in the reaction.
Conservation in Chemical Reactions Quick Check
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Question
Use the equation and the table to answer the question.
FeCl3 + 3H2O → Fe(OH)3 + 3HCl
Element Mass of an Atom (amu)
Fe 56
Cl 35
H 1
O 16
Iron chloride and water react according to the equation shown. The table shows the atomic masses of the elements involved in the reaction. What is the total mass of the reactants?
(1 point)
Responses
215 amu
215 amu
108 amu
108 amu
179 amu
179 amu
161 amu
161 amu
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page 18 of 18
To find the total mass of the reactants, we need to calculate the total mass of FeCl3 and 3H2O.
For FeCl3:
Mass of Fe = 56 amu
Mass of Cl (3 atoms) = 35 amu * 3 = 105 amu
Total mass of FeCl3 = 56 amu + 105 amu = 161 amu
For 3H2O:
Mass of H (6 atoms) = 1 amu * 6 = 6 amu
Mass of O (3 atoms) = 16 amu * 3 = 48 amu
Total mass of 3H2O = 6 amu + 48 amu = 54 amu
Total mass of the reactants = Total mass of FeCl3 + Total mass of 3H2O = 161 amu + 54 amu = 215 amu
Therefore, the total mass of the reactants is 215 amu.
In a chemical reaction, two molecules with a total mass of 76 amu react to form a single molecule. What is the mass of the molecule that is formed?(1 point)
Responses
228 amu
228 amu
38 amu
38 amu
152 amu
152 amu
76 amu
76 amu