1: Chemical Changes & Conservation of Mass
Passage
•
Science
•
8th Grade
•
Medium
Anchen Besselaar
Used 3+ times
FREE Resource
15 questions
Show all answers
1.
MULTIPLE CHOICE QUESTION
1 min • 1 pt
Which statement best distinguishes reactants from products in a chemical reaction?
Reactants are starting substances that undergo change
Reactants are new substances formed after change
Products are starting substances present before change
Products are unchanged substances that do not participate
2.
MULTIPLE CHOICE QUESTION
1 min • 1 pt
In Lavoisier’s sealed-container experiment heating mercury(II) oxide produced oxygen gas and liquid mercury. What did he learn about the total mass?
Total mass of reactants is greater than products
Total mass of reactants equals total mass of products
Total mass of reactants is less than products
Total mass of reactants changes unpredictably
3.
MULTIPLE CHOICE QUESTION
1 min • 1 pt
A student heats 12.0 g of copper carbonate in a sealed flask. It decomposes to 4.8 g of carbon dioxide and a solid. According to the law of conservation of mass, what is the mass of the solid produced?
12.0 g of solid remains after reaction
7.2 g of solid remains after reaction
2.4 g of solid remains after reaction
4.8 g of solid remains after reaction
4.
MULTIPLE CHOICE QUESTION
1 min • 1 pt
What does the coefficient “2” in 2NaOH(aq) indicate in a chemical equation?
Two charges on hydroxide ions
Two molecules of water produced
Two atoms of sodium in hydroxide
Two units of sodium hydroxide react
5.
MULTIPLE CHOICE QUESTION
1 min • 1 pt
Which symbol in a chemical equation shows that products are formed from reactants?
Plus sign indicates produces or yields
An arrow symbol indicates produces or yields
Heat label indicates produces or yields
Aqueous symbol indicates produces or yields
6.
MULTIPLE CHOICE QUESTION
1 min • 1 pt
In the reaction NiCl2(aq) + 2NaOH(aq) → Ni(OH)2(s) + 2NaCl(aq), how many units of NaCl form when one unit of NiCl2 reacts with two units of NaOH?
One unit of sodium chloride
Four units of sodium chloride
Two units of sodium chloride
Three units of sodium chloride
7.
MULTIPLE CHOICE QUESTION
1 min • 1 pt
Which statement best explains why coefficients, not subscripts, are changed when balancing chemical equations?
Changing subscripts changes the type of compound formed in the reaction
Changing subscripts makes counting atoms simpler and quicker
Subscripts only apply to gases and not to solids or liquids
Coefficients cannot change the total number of atoms present
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