Question

Question
1
Question
2
Question
3
A)
Which statement best describes the law of conservation of mass?
(1 point)
Matter cannot be created or destroyed in a chemical reaction.
Chemical symbols are used to show atom balance before and after a reaction.
Reactants in a chemical reaction rearrange to form a new substance or substances.
Reactants and products cannot escape from a closed system.
A)
Which parts must be balanced in a chemical equation?
(1 point)
energy on the reactant and product sides
numbers of reactant and product atoms
numbers of reactant and product molecules
states of reactants and products
A)
In a chemical reaction, two molecules are rearranged to produce two new molecules. Reactant 1 hasa mass of 12 g. Reactant 2 has a mass of 23 g. The mass of product 1 is 15 g. The mass of product 2 is
_____.
(1 point)
35 g
20 g
27 g
11 g
Question
4
Question
5
A)
Which example is a closed system?
(1 point)
the atmosphere of a planet
the human body
a sealed jar of salad dressing
a bowl of punch at a gathering
A)
Use the chemical equation to answer the question.
2O
+ CH
→ ?H
O + CO
How many molecules of water are produced in the reaction?
(1 point)
2
4
2
2
two
one
four
eight

Answer 1

1) Matter cannot be created or destroyed in a chemical reaction.

2) Numbers of reactant and product atoms.

3) 20 g.

4) A sealed jar of salad dressing.

5) 2 molecules of H2O.