Question

1. Reactions follow the law of conservation of mass.
a.) True
b.) False
Answer: True
2. Reactants are the materials used in a chemical reaction.
a.) True
b.) False
Answer: True
3. In a chemical equation, the mass on the left of the arrow equals the mass on the right.
a.) True
b.) False
Answer: True
4. Diatomic molecules contain two atoms.
a.) True
b.) False
Answer: True
5. Coefficients are the numbers written before a symbol or formula.
a.) True
b.) False
Answer: True
6. (aq) stands for a solution involving any liquids.
a.) True
b.) False
Answer: False
7. A synthesis reaction involves the combination of two or more substances to form a compound.
a.) True
b.) False
Answer: True
8. In a single replacement reaction, sodium (Na) does not replace hydrogen.
a.) True
b.) False
Answer: False
9. Metals can replace nonmetals.
a.) True
b.) False
Answer: False
10. Combustion occurs when a substance combines with oxygen to produce light and heat.
a.) True
b.) False
Answer: True
Thank you in advance!

Answer 1

All of these look ok to me with my only misgivings about 9. Technically, if I react Na metal with HCl, I get MgCl2 + H2 which looks to me as if a metal is replace a non-metal. And I can think of a number of redox reactions in which the metal is oxidized and the non-metal is reduced (although those may NOT be replacement reactions).

Answer 2

zeros at the end of measurements may not be significants