chemistry knowledge questions

Question 1

In a chemical reaction no atoms are lost or gained this is called the:

Answer 1

conservation of mass

Question 2

The sum of protons and neutrons is called the _________ number

Answer 2

mass

Question 3

The atomic number of an atom is the number of ___________

Answer 3

protons (or electrons)

Question 4

The sum of the mass of all the atoms in a compound is called the _______ ________ mass

Answer 4

relative formula

Question 5

What is the term for the molecules that react in a reaction?

Answer 5

reactants

Question 6

What is the term for the molecules formed in a reaction?

Answer 6

products

Question 7

The apparent mass of the products in a reaction could decrease if one of the products is a:

Answer 7

gas

Question 8

Why does a chemical formula equation need balancing?

Answer 8

Because mass is conserved/no atoms lost or gained

Question 9

Avogadro’s number is:

Answer 9

6.02x10 to the power of 23

Question 10

The mass of one mole of a substance in grams is numerically equal to its ___________

Answer 10

relative formula mass

Question 11

What two things do you need to know to calculate the concentration of a solution?

Answer 11

mass of solute and volume of solvent

Question 12

What is the standard unit for the concentration of a substance?

Answer 12

g/dm squared

Question 13

In a chemical reaction, if one reactant is in excess, the other reactant is known as what?

Answer 13

limiting reactant