Science Year 10 Term 1

Question 1

What are the key components of a first-hand investigation?

Answer 1

Collecting valid and reliable data, following safety procedures, and making accurate observations.

Question 2

How can you improve the reliability of an experiment?

Answer 2

By repeating trials, using consistent methods, and ensuring accurate measurements.

Question 3

What is the difference between validity and reliability in an experiment?

Answer 3

Validity refers to whether the experiment tests what it is supposed to, while reliability refers to the consistency of the results.

Question 4

What is accuracy in scientific experiments?

Answer 4

Accuracy is how close a measurement is to the true value.

Question 5

How do you present scientific data effectively?

Answer 5

Using tables, graphs, and appropriate scientific language and conventions.

Question 6

What happens to atoms during a chemical reaction?

Answer 6

Atoms are rearranged to form new substances; they are neither created nor destroyed.

Question 7

What is the Law of Conservation of Mass?

Answer 7

Mass is neither created nor destroyed in a chemical reaction; total mass of reactants = total mass of products.

Question 8

What are the types of chemical reactions you need to know?

Answer 8

Combustion, acid reactions (with metals and carbonates), corrosion, precipitation, neutralisation, and decomposition.

Question 9

What is a combustion reaction?

Answer 9

A reaction where a hydrocarbon reacts with oxygen, releasing heat and light energy.

Question 10

How do you write a word equation for a chemical reaction?

Answer 10

Reactant(s) → Product(s), e.g., Magnesium + Hydrochloric acid → Magnesium chloride + Hydrogen gas.

Question 11

What is the importance of balancing chemical equations?

Answer 11

To ensure the Law of Conservation of Mass is followed.

Question 12

What is a neutralisation reaction?

Answer 12

A reaction between an acid and a base that produces a salt and water.

Question 13

What is an exothermic reaction?

Answer 13

A reaction that releases heat energy (e.g., combustion).

Question 14

What is an endothermic reaction?

Answer 14

A reaction that absorbs heat energy (e.g., photosynthesis).

Question 15

How can you identify if a reaction is exothermic or endothermic?

Answer 15

Exothermic reactions release heat (feel hot), while endothermic reactions absorb heat (feel cold).

Question 16

What factors should be considered when designing an experiment?

Answer 16

Independent variable, dependent variable, control variables, and method.

Question 17

What is a risk assessment in an experiment?

Answer 17

A process of identifying potential hazards and implementing safety precautions.

Question 18

Why is it important to graph data in experiments?

Answer 18

To visually identify trends, patterns, and relationships in data.

Question 19

Why do different elements produce different flame colors in a flame test?

Answer 19

Because electrons absorb and release specific amounts of energy, emitting characteristic colors.

Question 20

What is the relationship between electron arrangement and the periodic table?

Answer 20

The number of electron shells and valence electrons determines an element’s chemical properties.

Question 21

What are the reactants and products in a combustion reaction?

Answer 21

Reactants: Fuel (hydrocarbon) + Oxygen → Products: Carbon dioxide + Water + Energy.

Question 22

What are the reactants and products of an acid-metal reaction?

Answer 22

Acid + Metal → Salt + Hydrogen gas.

Question 23

What are the reactants and products of an acid-carbonate reaction?

Answer 23

Acid + Carbonate → Salt + Carbon dioxide + Water.

Question 24

What is corrosion?

Answer 24

A slow chemical reaction where a metal reacts with oxygen and water to form rust (iron oxide).

Question 25

What is precipitation in chemistry?

Answer 25

A reaction where two soluble substances form an insoluble solid (precipitate).

Question 26

What is a decomposition reaction?

Answer 26

A reaction where a single compound breaks down into two or more simpler substances.

Question 27

What is a neutralisation reaction?

Answer 27

A reaction between an acid and a base that produces a salt and water.

Question 28

What are some signs that a chemical reaction has occurred?

Answer 28

Formation of a precipitate, color change, gas production (bubbles or fizzing), temperature change, light or sound emission.

Question 29

How can you test for hydrogen gas?

Answer 29

Use the pop test – insert a lit splint into the gas; if it pops, hydrogen is present.

Question 30

How can you test for carbon dioxide?

Answer 30

Bubble the gas through limewater; if it turns cloudy, carbon dioxide is present.

Question 31

How can you test for oxygen gas?

Answer 31

Insert a glowing splint into the gas; if it relights, oxygen is present.

Question 32

Why must chemical equations be balanced?

Answer 32

To satisfy the Law of Conservation of Mass—atoms cannot be created or destroyed.

Question 33

Balance this equation: H₂ + O₂ → H₂O

Answer 33

2H₂ + O₂ → 2H₂O

Question 34

Balance this equation: CaCO₃ → CaO + CO₂

Answer 34

Already balanced

Question 35

Balance this equation: Na + Cl₂ → NaCl

Answer 35

2Na + Cl₂ → 2NaCl

Question 36

What does the Law of Conservation of Mass state?

Answer 36

The mass of any one element remains the same before and after a chemical reaction.

Question 37

Why is mass conserved in chemical reactions?

Answer 37

Atoms cannot be created or destroyed; they are only rearranged.

Question 38

What is the rate of a chemical reaction?

Answer 38

The speed at which a chemical reaction occurs.

Question 39

How does the number of collisions affect the reaction rate?

Answer 39

More collisions lead to more reactions, increasing the reaction rate.

Question 40

What is activation energy?

Answer 40

The minimum energy required for a reaction to occur.

Question 41

What are the three requirements for a chemical reaction to happen?

Answer 41

1. Reactants must collide. 2. Molecules must have sufficient energy. 3. Molecules must have the correct orientation.

Question 42

How does concentration affect reaction rate?

Answer 42

Higher concentration → More particles → More collisions → Faster reaction.

Question 43

How does surface area affect reaction rate?

Answer 43

Smaller particles → Greater surface area → More collisions → Faster reaction.

Question 44

How does temperature affect reaction rate?

Answer 44

Higher temperature → More kinetic energy → More collisions → Faster reaction.

Question 45

How do catalysts affect reaction rate?

Answer 45

Catalysts lower activation energy, leading to more successful collisions.

Question 46

What is the first step in balancing a chemical equation?

Answer 46

Assign variables to the coefficients of each reactant and product.

Question 47

Why do we multiply all coefficients by a common factor when balancing equations?

Answer 47

To ensure all coefficients are whole numbers.

Question 48

What is an exothermic reaction?

Answer 48

A reaction that releases heat and light.

Question 49

What is an endothermic reaction?

Answer 49

A reaction that absorbs heat from the surroundings.

Question 50

What is a neutralization reaction?

Answer 50

A reaction between an acid and a base that forms salt and water.

Question 51

What happens when acids react with metals?

Answer 51

They produce salt and hydrogen gas.

Question 52

What is the general formula for a decomposition reaction?

Answer 52

AB → A + B

Question 53

What is a combustion reaction?

Answer 53

A reaction where a substance reacts with oxygen to produce heat and light.

Question 54

What is a mnemonic to remember the metal reactivity series?

Answer 54

"Please Stop Calling Me A Careless Zebra Instead Try Learning How Copper Saves Gold."

Question 55

Which metals are the most reactive?

Answer 55

Potassium, Sodium, and Calcium.

Question 56

Which metals are the least reactive?

Answer 56

Copper, Silver, and Gold.

Question 57

What is the solubility rule mnemonic 'NAG SAG' used for?

Answer 57

To remember generally soluble compounds: Nitrates, Acetates, Group 1, Sulfates (exceptions: Ag, Hg, Pb, Sr, Ca, Ba), Ammonium, Group 17 (exceptions: Ag, Hg, Pb).

Question 58

What is an ionic compound?

Answer 58

A compound formed when one atom transfers electrons to another, creating charged ions.

Question 59

What are two key properties of ionic compounds?

Answer 59

High melting points and they conduct electricity in solution.

Question 60

What is a covalent compound?

Answer 60

A compound where atoms share electrons to complete their outer shells.

Question 61

What are two key properties of covalent compounds?

Answer 61

Low melting points and poor electrical conductivity.

Question 62

What are two properties of acids?

Answer 62

Sour taste and they turn blue litmus paper red.

Question 63

What are two properties of bases?

Answer 63

Bitter taste and they turn red litmus paper blue.

Question 64

What is the key difference between a strong acid and a weak acid?

Answer 64

A strong acid completely dissociates in water, while a weak acid only partially dissociates.