Question

Question
1
Question
2
A)
According to the law of conservation of mass, which statement about chemical reactions is alwaystrue?
(1 point)
The number of substances in the reactants is the same as the number substances in the products.
The states of the substances in the reactants is the same as the states of the substances in the products.
The number of atoms of each element in the reactants is the same as the number of atoms of eachelement in the products.
The number of molecules in the reactants is the same as the number of molecules in the products.
A)
When 1 mole of nitrogen gas (N
) reacts with 3 moles of hydrogen gas (H
), how many moles ofammonia (NH
) are produced?
(1 point)
2
2
3
1 mole
2 moles
3 moles
4 moles
Question
3
Question
4
A)
Sulfur trioxide gas combines with water to form a single product.
SO
+ H
O → ?
Based on the law of conservation of mass, which option is the product of the reaction?
(1 point)
3
2
H
S
O
2
2
4
HSO
4
H
SO
2
4
H
SO
2
3
A)
Lead (II) nitrate as Pb(NO
)
and potassium iodide as KI combine to form the products shown.
2 KNO3
+ PbI
How many moles of each reactant are involved in the reaction?
(1 point)
3
2
2
2 moles of lead (II) nitrate and 2 moles of potassium iodide
1 mole of lead (II) nitrate and 2 moles of potassium iodide
2 moles of lead (II) nitrate and 1 mole of potassium iodide
1 mole of lead (II) nitrate and 1 mole of potassium iodide
Question
5
A)
In a reaction, 1 mole of silver nitrate combines with 1 mole of sodium chloride.
AgNO
+ NaCl
Which statement about the product is justified by the law of conservation of mass?
(1 point)
3
There will be 2 moles of sodium (Na) in the product.
There will be 1 mole of silver (Ag) in the product.
There will be two molecules in the product.
There will be five atoms in the product.

Answer 1

Here are the answers with brief justifications:

1) The number of atoms of each element in the reactants is the same as the number of atoms of each element in the products.
- (Conservation of mass requires each element’s atoms be conserved.)

2) 2 moles
- N2 + 3H2 → 2NH3, so 1 mol N2 + 3 mol H2 → 2 mol NH3.

3) H2SO4 (sulfuric acid)
- SO3 + H2O → H2SO4.

4) 1 mole of lead(II) nitrate and 2 moles of potassium iodide.
- Pb(NO3)2 + 2 KI → 2 KNO3 + PbI2.

5) There will be 1 mole of silver (Ag) in the product.
- AgNO3 + NaCl → AgCl + NaNO3, so 1 mol Ag in the products.