Question

Liquid 1 and Liquid 2 react to produce a solid and a gas. Which of the following expressions correctly shows how to determine mass of gas:
A.$\left( {{\text{mass of liquid 1}}} \right){\text{ + }}\left( {{\text{mass of liquid 2}}} \right){\text{ - }}\left( {{\text{mass of solid}}} \right)$
B.$\left( {{\text{mass of liquid 1}}} \right){\text{ + }}\left( {{\text{mass of liquid 2}}} \right){\text{ + }}\left( {{\text{mass of solid}}} \right)$
C.$\left( {{\text{mass of liquid 1}}} \right){\text{ }} \times {\text{ }}\left( {{\text{mass of liquid 2}}} \right){\text{ }} \div \left( {{\text{mass of solid}}} \right)$
D.$\left( {{\text{mass of liquid 1}}} \right){\text{ - }}\left( {{\text{mass of liquid 2}}} \right){\text{ - }}\left( {{\text{mass of solid}}} \right)$

Answer 1

To answer this question, you should recall the concept of different laws of chemical combination with their key points. Chemistry refers to the study of the transformation of matter from one form to the other which results from the combination of two different types of matter. The Law of Conservation of Mass states that the mass of a closed system will stay constant over time, no matter the processes occurring inside the system.

Complete step by step answer:
The Law of Conservation of Mass states that the mass of a closed system will stay constant over time, no matter the processes occurring inside the system. Mass can't be made or destroyed but, it is often rearranged and altered into differing types of particles. For example, when water is made from hydrogen and oxygen, atoms of every element aren't lost or created; just rearranged. According to the law of conservation of mass:
$\left( {{\text{mass of liquid 1}}} \right){\text{ + }}\left( {{\text{mass of liquid 2}}} \right){\text{ = }}\left( {{\text{mass of solid}}} \right){\text{ + }}\left( {{\text{mass of gas}}} \right)$.
This means that $\therefore {\text{Mass of gas = mass of Liquid 1 + mass of Liquid 2 - mass of solid}}$.

Thus, the correct answer is option A.

Note:
1. The Law of Constant Composition: A compound always has an equivalent proportion of elements by mass. The Law of Multiple Proportions: If two elements combine to make quite one compound, then the masses of the weather that combine are given during a small whole-number ratio.
2. Gaseous Volumes: This law states that when gases are produced or combined in a chemical reaction, they do so in a simple ratio by volume given that all the gases are at the same temperature and pressure. This law can be considered as another form of the law of definite proportions.
3. Avogadro’s Law: It stated that under the same conditions of temperature and pressure, an equal volume of all the gases contains an equal number of molecules. This implies that 2 litres of hydrogen will have the same number of molecules as 2 litres of oxygen given that both the gases are at the same temperature and pressure.