Answer:
A
Explanation:
The law of conservation of mass states that matter can never be created nor destroyed but can be converted from one form to another.
The law of conservation of energy posits that energy cannot be created nor destroyed but can be converted from one form to another.
These laws are the basic laws of existence. Although the laws have been adjusted, they still form the basic principle behind several scientific laws and are responsible for a whole lot of scientific advancements.
While the first law focuses on matter and the content of matter in a body, the second law basically focuses on energy. The second law serves to support the inter convertibility behind the several forms or types of energy.
For example, to do many useful work at home, it is found that energy is converted from its electric form to say heat in an electric iron to press our clothes.
Also, the first law is a fundamental principle useful in the balancing of our chemical equations.
Answer:

Explanation:
We are asked to find the density of a brick. Density is a substance's mass per unit volume. The formula for calculating density is as follows.

The mass of the brick is 100 grams and the volume is 25 cubic centimeters.
Substitute the values into the formula.

Divide.

The density of the brick is <u>4 grams per cubic centimeter.</u>
Answer:
CH
Explanation:
We have to obtain the mass of carbon and hydrogen in CO2 and H2O respectively.
For carbon in CO2;
0.845 * 12/44 = 0.23 g
For hydrogen in H20;
0.173 * 2/18 = 0.019 g
We convert the masses to moles of carbon and hydrogen
For carbon - 0.23/ 12 = 0.019 moles
For hydrogen - 0.019/1 = 0.019 moles
Dividing by 0.019 moles for carbon and hydrogen we have the emperical formula of the compound as CH