Chemistry Multiple Choice Questions on “Laws of Chemical Combination”.
1. How many basic laws are required to govern the combination of elements to form compounds?
a) 6
b) 5
c) 4
d) 1
Answer: b
Clarification: Five basic laws are required to govern the combination of elements to form compounds. They are Law of Conservation of Mass, Law of Definite Proportions, Law of Multiple Proportions, Gay Lussac’s Law of Gaseous Volumes, and Avogadro’s Law.
2. Who proposed Law of Conservation of Mass?
a) Antoine Lavoisier
b) Joseph Proust
c) Lorenzo Romano
d) Joseph Louis
Answer: a
Clarification: Antoine Lavoisier conducted many experiments regarding combustion and noticed various physical and chemical changes and there is no change in overall mass. Hence he came to a conclusion that mass can neither be created nor destroyed i.e. Law of Conservation of Mass.
3. What did Joseph Proust state regarding Law of Definite Proportions?
a) A given mixture always contains absolutely the same proportion of elements by weight
b) A given compound always contains absolutely the same proportion of moles by weight
c) A given compound always contains absolutely the same proportion of elements by volume
d) A given compound always contains absolutely the same proportion of elements by weight
Answer: d
Clarification: When Joseph Proust worked about the composition of elements present in a compound experimentally, he found out that it was the same for all the samples he took. Joseph Louis concluded that from any source, a particular compound always contains the same elements in the same proportion by mass/weight.
4. What did Dalton propose?
a) Law of Multiple Proportions
b) Avogadro’s Law
c) Law of Definite Composition
d) Law of Conservation of Mass
Answer: a
Clarification: Two or more elements those are given, may combine to form more than one compound, the masses of one element that will combine with the given mass of the other elements, would be in the ratio of whole numbers is the law of Multiple Proportions.
5. Who proposed the Law of Definite Composition?
a) Joseph Proust
b) Lorenzo Romano
c) Joseph Louis
d) Antoine Lavoisier
Answer: a
Clarification: Joseph Proust worked about the composition of elements present in a compound experimentally, he concluded that from any source, a particular compound always contains the same elements in the same proportion by mass/weight.
6. Law of Definite Composition is also known as ________
a) Law of Multiple Proportions
b) Avogadro’s Law
c) Law of Definite Proportion
d) Law of Conservation of Mass
Answer: c
Clarification: Joseph Proust worked about the composition of elements present in a compound experimentally, he concluded that from any source, a particular compound always contains the same elements in the same proportion by mass/weight. Hence it can also be known as the Law of Definite Proportion.
7. The volumes of hydrogen & oxygen when combined bear a simple ratio of 2:1.This is explained by ________
a) Law of Multiple Proportions
b) Avogadro’s Law
c) Law of Definite Proportion
d) Gay Lussac’s Law of Gaseous Volumes
Answer: d
Clarification: When gases combine or as written in a chemical reaction they combine in a simple ratio by volume, provided that all gases are at the same temperature and given pressure, this is called Gay Lussac’s Law of Gaseous Volumes and is proposed by Joseph Louis.
8. Who proposed that equal volumes of all gases at the same temperature & given pressure should contain an equal number of molecules?
a) Antoine Lavoisier
b) Joseph Proust
c) Avogadro
d) Joseph Louis
Answer: c
Clarification: Avogadro’s law is an experimental gas law combining & relating the volume of a gas to the amount of substance of gas present i.e’ directly proportional. This law is valid only for ideal gases. And also only when the pressure and temperature of the given substance are constant.
9. Which of the following is not a law of chemical combination?
a) Law of Multiple Proportions
b) Avogadro’s Law
c) Law of Definite Proportion
d) Law of Conservation of volume
Answer: d
Clarification: Five basic laws are required to govern the combination of elements to form compounds. They are Law of Conservation of Mass, Law of Definite Proportions, Law of Multiple Proportions, Gay Lussac’s Law of Gaseous Volumes, and Avogadro’s Law.
10. Which of the following may be an incorrect statement?
a) Law of Definite Composition is also known as Law of Definite composition
b) Mass can neither be created nor destroyed is Law of Conservation of Volume
c) Antoine Lavoisier conducted many experiments regarding combustion
d) Five basic laws are required to govern the combination of elements to form compounds
Answer: b
Clarification: The correct statement is mass can neither be created nor destroyed is the Law of Conservation of Mass. On conducting many experiments regarding combustion and noticing various physical and chemical changes, there is no change in overall mass hence conservation of mass.