1. Chemical reactions
Test Review

2. A bread bag says “This product baked using a mold inhibitor” means
All natural ingredients
An ingredient that encourages the rising of yeast
An ingredient that helps prevent the growth of mold
Several different types of preservatives

3. Which of these is NOT evidence of a chemical reaction?
An iron nail changes to a brownish-orange color
An ice cube melts into liquid water
An antacid tablet produces bubbles of gas when placed in water
A piece of zinc raises the temperature of an acid as it reacts

4. According to the law of conservation of mass, how does the mass of the products in a chemical reaction compare with the mass of the reactants?
The mass of the products is greater
The mass of the reactants is greater
There is no relationship
The masses are equal

5. A shorthand method of writing a chemical reaction is a
Synthesis reaction
Coefficient
Chemical equation
catalyst

6. According to the law of conservation of mass, if two atoms of hydrogen are used as a reactant, how many atoms of hydrogen must be part of the product? 2 1 4

7. What is the solid called that separates out during a specific type of a reaction?
A precipitate
An inhibitor
A coefficient
A catalyst

8. The symbol  mean _____.
And
Aqueous
Yields
reactants

9. Which of these is a reason a catalyst is added to a chemical reaction?
To stabilize a substance
To speed up a reaction
To produce a greater amount of the catalyst
To prevent a compound from forming

10. Which of these is a product for the reaction shown below Pb(NO3)2 + 2Kl  Pbl2 + 2KNO3
PbI2 Pb KI

11. A scientist is studying a chemical reaction in which iron (Fe) and sulfur (S) react to produce iron sulfide (FeS). Which of these chemical equations correctly represents this reaction?
FeS  Fe + S
Fe + S  FeS
FeS + S  Fe
Fe + FeS  S

12. CaCO3  CaO + CO2 How much of CO2 is produced from the decomposition of 350g and CaCO3 if 114g of CaO are produced?
CaCO3  CaO + CO2 350g  114g + x -114g -114g 236g = x

13. A new substance was created
When silver coins are found in ancient shipwrecks, they are coated with a black crust. How would you know that a chemical change (and not physical change) caused the black crust to form?
A new substance was created

14. What do balanced chemical equations have to do with the law of conservation of mass?
A mass is the same before and after the chemical reaction. Each element has the same number of atoms on each side of the equation.

15. Exothermic – releases energy and heat
To develop a product that warms people’s hands, would you choose an exothermic or endothermic reaction to use? Why?
Exothermic – releases energy and heat

16. Explain why the sum of the coefficients on the reactant side of a balanced equation does not have to equal the sum of the coefficients on the product side of the equation.
Not every element gets a coefficient depends on the compounds that are created in the products