In water (H₂O) and hydrogen peroxide (H₂O₂), taking a FIXED mass of hydrogen (2 g), the masses of oxygen are 16 g and 32 g respectively. What law does this illustrate?
A.
Law of Definite Proportions — both compounds have same H:O ratio
B.
Law of Conservation of Mass — total mass of products = mass of reactants
C.
Gay-Lussac's Law — volume ratio of gases is a whole number
D.
Law of Multiple Proportions — ratio of oxygen masses (16:32 = 1:2) is a simple whole number ratio
D. Law of Multiple Proportions — ratio of oxygen masses (16:32 = 1:2) is a simple whole number ratio
14.
How does the Law of Multiple Proportions support the existence of atoms?
A.
It proves that atoms are arranged in shells around a nucleus
B.
It demonstrates that electrons are transferred during chemical reactions
C.
Simple whole number ratios of combining masses directly indicate that elements combine as discrete indivisible atoms in fixed numerical ratios — fractional atoms would give fractional ratios
D.
It shows that molecules are divisible into smaller particles
C. Simple whole number ratios of combining masses directly indicate that elements combine as discrete indivisible atoms in fixed numerical ratios — fractional atoms would give fractional ratios
15.
Sulphur dioxide (SO₂) contains sulphur and oxygen in a mass ratio of 1:1. Sulphur trioxide (SO₃) contains sulphur and oxygen in a mass ratio of 2:3. With 32 g of sulphur fixed, the masses of oxygen are 32 g (in SO₂) and 48 g (in SO₃). What is the ratio of these oxygen masses?
A.
3:2 (because SO₃ has more oxygen)
B.
1:2 (because SO₃ has one more oxygen than SO₂)
C.
32:48 = 2:3 (a simple whole number ratio — illustrating the Law of Multiple Proportions)
What is the correct statement of Gay-Lussac's Law of Combining Volumes?
A.
When gases combine or are produced in a chemical reaction, they do so in volumes that bear a simple whole number ratio to one another and to the products (if gaseous), all measured at the same temperature and pressure
B.
Gases react only in 1:1 volume ratios under all conditions
C.
Equal volumes of all gases contain equal numbers of molecules at all temperatures
D.
The volume of a gas is directly proportional to its temperature at constant pressure
A. When gases combine or are produced in a chemical reaction, they do so in volumes that bear a simple whole number ratio to one another and to the products (if gaseous), all measured at the same temperature and pressure
18.
The formation of water vapour from hydrogen and oxygen gases illustrates Gay-Lussac's Law. The volume ratio of H₂ to O₂ to H₂O (steam) is:
A.
1 : 1 : 1
B.
2 : 1 : 2 (two volumes of H₂ + one volume of O₂ → two volumes of water vapour)
