Key Concepts

Question 1

What is meant by the conservation of mass in chemical reactions?

Answer 1

That the mass of reactants is equal to the mass of the products.

Question 2

What is the chemical and word equation for calcium carbonate and hydrochloric acid?

Answer 2

Calcium carbonate + hydrochloric acid —> calcium chloride + carbon dioxide + water
CaCO3 + 2HCl —> CaCl2 + CO2 + H2O

Question 3

What happens to the mass if a gas is produced during the reaction?

Answer 3

The mass of the reaction would appear to decrease as the gas has escaped into the atmosphere so can no longer be accurately measured.

Question 4

What happens to the mass if a gas is one of the reactants?

Answer 4

The mass would appear to increase as the gas which couldn’t have been measured before is now being able to be measured.

Question 5

Go on Google and balance some equations

Answer 5

Check your answers

Question 6

What is the word and chemical equation for a reaction between lead nitrate and potassium iodide

Answer 6

Lead nitrate + potassium iodide —> lead iodide + potassium nitrate
Pb(NO) + 2KI —> PbI + 2KNO

Question 7

What is an element

Answer 7

A substance made up of only one type of atom

Question 8

What is a mixture

Answer 8

2 or more different non chemically bonded substances

Question 9

Define solvent

Answer 9

A liquid that can dissolve a solute

Question 10

What does impure mean

Answer 10

A mixture that will melt over a range of temperatures

Question 11

How do define a pure substance

Answer 11

Something that contains one type of particle and will have a fixed melting point,

Question 12

How does chromatography determine how soluble an ink is?

Answer 12

The amount that they move depends on how soluble they are in water.

Question 13

What is the retention factor?

Answer 13

Rf= distance travelled by compound / distance travelled by solvent

Question 14

What does the retention factor tell us?

Answer 14

Has no units, and is between 0-1. The distance travelled by the SPOT (not dye or ink) relative to the solvent, tells us how soluble it is.

Question 15

What are group 1 metals referred to as?

Answer 15

Alkali metals

Question 16

What are group 2 metals referred as?

Answer 16

Alkali earth metals

Question 17

What are group 7 elements known as

Answer 17

Halogens

Question 18

What are group 0 known as

Answer 18

Noble gases

Question 19

What are general properties of metals?

Answer 19

• high melting and boiling points
• good conductors of heat and electricity
• malleable
• dense

Question 20

What are general properties of non-metals?

Answer 20

• low melting and boiling points
• poor conductors of electricity (except graphite)
• brittle
• dull
• less dense

Question 21

What is the charge and mass of electrons?

Answer 21

Mass = negligible
Charge = -1

Question 22

What is the charge and mass of neutrons?

Answer 22

Mass = 1
Charge = 0

Question 23

What is the charge and mass of protons?

Answer 23

Mass = 1
Charge = +1

Question 24

What is the atomic number of an elements?

Answer 24

The number of protons

Question 25

What is the atomic mass of an element?

Answer 25

Protons + neutrons

Question 26

What is an isotope?

Answer 26

Atoms of an element with the same number of protons but a different number of neutrons

Question 28

How do calculate the relative atomic mass (Ar)?

Answer 28

(Mass of isotope x % of isotope) + (mass of isotope x % of isotope) / 100

Question 29

What is the relative atomic mass?

Answer 29

The weighted average of the masses of the isotopes of an element compared to a (relative element)

Question 31

What is the formula of a hydroxide ion.

Answer 31

OH-

Question 32

What is the formula of a carbonate ion?

Answer 32

CO3 2-

Question 33

What is the formula of a nitrate ion?

Answer 33

NO3 -

Question 34

What is the formula of a sulfate ion?

Answer 34

SO4 2-

Question 35

What is the formula of an ammonium ion?

Answer 35

NH4 +