Introduction to Science

Question 1

Can you list 5 lab rules?

Answer 1

1) Line up Quietly
2) Never Run
3) Bags Left Outside
4) Do not eat or drink in the laboratory
5) Report any breakages or spillages to the teacher

Question 2

What are the Four Aspects of Science?

Answer 2

Biology: The study of living things
Chemistry: The study of properties and matter
Physics: The study if motion, energy, and forces
Earth and Space: Studt of the interconnections between land, ocean, atmosphere, and life of our planet beyond.

Question 3

Describe the strtucture of a atom

Answer 3

Nucleus: Protons (+) and neutrons (neutral) in the center.
Electrons: Negatively charged, orbit around the nucleus.

Question 4

Protons

Answer 4

Protons are positively charged subatomic particles which are found in the nucleus of an atom.

Question 5

Neutrons

Answer 5

Neutrons are subatomic particles which have no charge. They are also found in the nucleus of an atom.

Question 6

Electrons

Answer 6

Electrons are negatively charged subatomic particles which are found in the electron cloud around the outside of the atom.

Question 7

What does the Atomic Number tell us?

Answer 7

Tells us the number of protons OR electrons in the atom

Question 8

What does the Mass Number tell us?

Answer 8

The mass number of an element is determined by the number of protons and neutrons combined.

Question 9

Define an ion as an electrically charged atom or group of atoms

Answer 9

Ions are formed when the number of protons in an atom does not equal the number of electrons. If more protons are present, the ion is positive and is known as a cation; if more electrons are present, the ion is negative and referred to as an anion

Question 10

What is the valence shell of an atom?

Answer 10

The valence shell is the outermost electron shell of an atom

Question 11

What charge does an atom have when it gains electrons?

Answer 11

When an atom gains electrons, it becomes negatively charged

Question 12

How to calculate neutrons

Answer 12

Neutrons = Mass number - Atomic number

Question 13

Why do atoms lose or gain electrons?

Answer 13

to become more stable and have a full valence shell.

Question 14

Explain why chloride ion and calcium ion have the same number of electrons.

Answer 14

Cl⁻ has 18 electrons by gaining 1, and Ca²⁺ has 18 by losing 2. They both end up with 18 electrons.

Question 15

What is an ion?

Answer 15

An ion is an atom or molecule with a charge from losing or gaining electrons.

Question 16

Write the ion (and charges) these atoms form:
a) Sulfur
b) Beryllium
c) Chlorine
d) Boron

Answer 16

a) Sulfur: S²⁻
b) Beryllium: Be²⁺
c) Chlorine: Cl⁻
d) Boron: B³⁺

Question 17

Explain why group 14 and 18 don’t form ions

Answer 17

Group 14 shares electrons, forming covalent bonds. Group 18 has a full valence shell, making them stable and unreactive.

Question 18

Write the atoms (and numbers) found in the following compounds
a) Ca(NO₃)₂:
b) Mg(NO₃)₂
c) NaHCO₃
d) NH₄Cl:

Answer 18

a) Ca(NO₃)₂: 1 Ca, 2 N, 6 O
b) Mg(NO₃)₂: 1 Mg, 2 N, 6 O
c) NaHCO₃: 1 Na, 1 H, 1 C, 3 O
d) NH₄Cl: 1 N, 4 H, 1 Cl

Question 19

Write the Explain why Aluminium Iodide is written as AlI3

Answer 19

Aluminium Iodide is AlI₃ because Al has a +3 charge and I has a -1 charge. Three iodide ions balance one aluminum ion.

Question 20

Are Atoms in groups 1, 2, 13, 15, 16 and 17 stable or unstable, why?

Answer 20

Unstable because they don’t have a full (or half full) valence shell of electrons.

Question 21

Are ions stable or unstable, why?

Answer 21

Stable because they have a full valence shell of electrons.

Question 22

Are Atoms in groups 1, 2, 13, 15, 16 and 17 charged or neutral, why?

Answer 22

Neutral because the number of protons is the same as the number of electrons

Question 23

What are reactants?

Answer 23

Reactants are substances that start a chemical reaction.

Question 24

What are products?

Answer 24

Products are substances that are produced in the reaction.

Question 25

1) Magnesium reacted with hydrochloric acid to make magnesium chloride and hydrogen gas.

2) Calcium reacted with oxygen in the air to make calcium oxide.

3) Iron rusts in air by reacting with oxygen gas to make iron (III) oxide.

4) Sulfuric acid reacts with calcium carbonate to produce calcium sulfate, carbon dioxide gas and water.

5) Sodium reacts with water to produce sodium hydroxide and hydrogen gas.

6) Copper reacts with sulfur to make copper sulfide

Answer 25

1) Magnesium + Hydrochloric Acid → Magnesium Chloride + Hydrogen Gas
Mg + 2 HCl → MgCl₂ + H₂

2) Calcium + Oxygen → Calcium Oxide
2 Ca + O₂ → 2 CaO

3) Iron + Oxygen → Iron (III) Oxide
4 Fe + 3 O₂ → 2 Fe₂O₃

4) Sulfuric Acid + Calcium Carbonate → Calcium Sulfate + Carbon Dioxide + Water
H₂SO₄ + CaCO₃ → CaSO₄ + CO₂ + H₂O

5) Sodium + Water → Sodium Hydroxide + Hydrogen Gas
2 Na + 2 H₂O → 2 NaOH + H₂

6) Copper + Sulfur → Copper Sulfide
Cu + S → CuS

Question 26

What are Balancing Symbol Equations

Answer 26

A word or balanced equation shows a reaction. A word or balanced equation demonstrates a reaction, in which the reactant mass equals the product mass, and the number of atoms is conserved.

Question 27

What is a diatomic element?

Answer 27

These are elements that are always found in a molecule with two atoms. You need to learn these so you can balance equations correctly

Question 28

Balance these equations

1) H₂ + O₂ → H₂O

2) N₂ + H₂ → NH₃

3) CH₄ + O₂ → CO₂ + H₂O

Answer 28

1) 2 H₂ + O₂ → 2 H₂O

2) N₂ + 3 H₂ → 2 NH₃

3) CH₄ + 2 O₂ → CO₂ + 2 H₂O

Question 29

Why do we need to balance chemical equations?

Answer 29

We balance equations to conserve mass, show atom numbers, ensure accuracy, and predict yields.

Question 30

Why are metal ions positively charged?

Answer 30

Metal ions are positively charged because they lose electrons.

Question 31

1) What is the formula for Magnesium Sulfide?
2) What is the formula for Aluminium Sulfate?
3) What is the formula for Calcium Nitrate?
4) What is the formula for Lithium Phosphate?

Answer 31

1) MgS
2) Al₂(SO₄)₃
3) Ca(NO₃)₂
4) Li₃PO₄

Question 32

How to correctly and safely light a Bunsen Burner

Answer 32

1) Put on safety glasses.
2) Connect the gas tube to the gas pipe (making sure the gas is switched off).
3) Open the air hole.
4) Pick up the striker.
5) Turn on the gas and use the striker to create a spark above the Bunsen.
6) Once the gas ignites, turn the Bunsen to the safety flame.
7) If the Bunsen doesn’t ignite after 10 seconds, turn off the gas and raise your hand to speak to your teacher.