Metals & Reactivity
What common property do all metals share?
A: They conduct electricity.
What reaction type is: Metal + Oxygen → Metal Oxide?
A: Combination/Synthesis.
What is an ore?
A: Rock containing enough metal for profitable extraction.
A bike travels 30 km in 2 hours. What is its speed?
A: 15 km/h.
Two forces (20 N left and 30 N right) act on an object. What is the resultant force?
A: 10 N right.
Name 3 metals often found as pure elements (native) in nature?
A: Gold, silver, platinum (also copper)
What products form when sodium reacts with hydrochloric acid?
A: Sodium chloride and hydrogen gas.
What is the definition of a composite material?
A material made by combining two or more materials with different properties
A runner moves at 5 m/s for 1 minute. How far do they travel?
A: 300 meters
A 10 kg object accelerates at 2 m/s². What force is applied?
A: 20 N
Zinc reacts with dilute acid, but gold does not. Which is less reactive?
Gold.
Magnesium displaces zinc from zinc oxide. Why is this possible?
A: Magnesium is more reactive than zinc.
Give three properties of ceramics (e.g., brick)?
A: Hard, brittle, high melting point.
A train covers 240 km at 80 km/h. How long does it take?
3 hours.
If gas volume increases at constant temperature, what happens to pressure (Boyle’s Law)?
A: Pressure decreases.
Why is aluminium extracted by electrolysis, not carbon reduction?
A: Aluminium is more reactive than carbon.
Magnesium (Group 2) and oxygen (Group 6) form magnesium oxide. What is its formula?
MgO
Starch and cellulose are natural ________.
A: Polymers.
A distance-time graph shows a flat line for 5 seconds, then a steep straight slope. Describe the motion.
A: Stationary, then fast constant speed.
If gas temperature rises at constant pressure, what happens to volume (Charles’s Law)?
A: Volume increases.
Tin reacts with acid but not steam; lithium reacts with cold water. Which is more reactive?
A: Lithium.
Metal X displaces Y from Y’s compound but not Z from Z’s compound. Order their reactivity (high to low).
A: Z > X > Y.
Why is steel-reinforced concrete stronger than plain concrete?
A: It resists both compression and tension forces.
A car travels 60 km to a town at 40 km/h and returns at 60 km/h. What is the average speed?
A: 48 km/h.
When air in a sealed bottle is heated, how do molecule speed and pressure change?
Hint: Charles' Law is T∝P
A: Molecule speed increases; pressure increases.