Y9 - T2: Fundamental Ideas In Chemistry

Question 1

What is an Element?

Answer 1

A substance made up of only one type of atom. An element can’t be broken down chemically into any simpler substance.

Question 2

What is a Compound?

Answer 2

A substance made when two or more elements are chemically bonded together.

Question 3

What is a Mixture?

Answer 3

Wo or more substances that are not chemically bonded together and retain their distinct identities.

Question 4

What does the Term ‘Mole’ mean?

Answer 4

The mole is the unit for amount of substance.

Question 5

What is Avogadro’s number?

Answer 5

6.02x10^23

Question 6

What is a pure substance?

Answer 6

Something that contains only one substance.

Question 7

What is an Isotope?

Answer 7

Atoms of the same element with the same number of protons and electrons but a different number of neutrons.

Question 8

What is a diatomic molecule?

Answer 8

Consists of two atoms of the same non-metal element chemically bonded together.

Question 9

What does the atomic number tell you?

Answer 9

How many protons are in the nucleus of an element. This also equals the number of electrons.

Question 10

What is the symbol for Relative Formula Mass?

Answer 10

Mr

Question 11

What is the unit for Relative Atomic Mass?

Answer 11

Ar

Question 12

What is the Ar?

Answer 12

The Relative Atomic Mass of a substance.

Question 13

What is the Mr?

Answer 13

The relative formula mass of a substance made up of molecules is the sum of the relative atomic masses of the atoms in the numbers shown in the formula.

Question 14

What is the Law of conservation of mass?

Answer 14

No atoms are created or destroyed in a chemical reaction. Instead, they just join together in a different way.

Question 15

What does the Mass equal?

Answer 15

Relative Formula Mass X Number of Moles

Question 16

What does the Relative Formula Mass equal?

Answer 16

Mass / Number of Moles

Question 17

What does the Number of Moles equal equal?

Answer 17

Mass / Relative Formula Mass

Question 18

Calculate the number of moles of carbon dioxide molecules in 22 g of CO2.

Answer 18

Ar (relative atomic mass) of carbon, C = 12

Ar of oxygen, O = 16

Mr (relative formula mass) of carbon dioxide, CO2 = 12 + 16 + 16 = 44

number of moles = 22 ÷ 44 = 0.5 mol

Question 19

Calculate the mass of 2 mol of carbon dioxide (CO2).

Answer 19

mass = number of moles × relative formula mass = 2 × 44 = 88 g

Question 20

What is the equation for percentage by mass?

Answer 20

% by mass = (atomic mass (total) ÷ formula mass) x 100

Question 21

What does the atomic mass tell you?

Answer 21

The number of protons plus neutrons there are in the nucleus of an element.