topic C3- Quantitative chemistry

Question 1

What is the value of a mole

Answer 1

6.02 ✖️ 10🔝23

Question 2

What is the meaning of conservation of mass

Answer 2

During a chemical reaction no atoms are destroyed and no atoms are created

Meaning that there is the same number and types of atoms on each side of the equation

Question 3

What is the reason of mass increasing

Answer 3

Its probably because one of the reactants is a gas that is found in the air

Before the reaction the gas is in the air because of this you cant account for its mass

Then the gas reacts to form a part of the product so now you can measure it

Question 4

What is the reason of mass decreasing

Answer 4

Its probably because one of the products is a gas

Before the reaction the reactants can be measured

Then of the vessel is not closed the gas would escape and as it is a gas you can not measure it

Question 5

How do you balance an equation using reacting masses

Answer 5

1) Divide the mass of each substance by its relative formula mass to find the number of moles
2) Divide the number of most for each substance by the smallest number of moles in the reaction
3) if any of the numbers aren’t whole numbers multiply all the numbers by the same amount so that they all become whole numbers
4) right the balance symbol equation for the reaction by putting these numbers in front of the chemical formula

Question 6

What is a limiting reaction

Answer 6

This is the reactant that used up in a reaction

Question 7

What is concentration

Answer 7

The amount of a substance in a certain volume of solution