Photosynthesis
Reactivity
Matter and Waves
Rates of Reaction
Biological Systems
100

What are the four requirements for photosynthesis?

Light, carbon dioxide, water, chlorophyll

100

What is an element?

A substance made of one type of atom

100

What are the three (standard) states of matter?

solid, liquid, gas (but there are more...)

100

What is a catalyst?

A substance that speeds up a reaction without being used up

100

What is meant by a habitat?

The place where an organism lives

200

Which tissue carries water around the plant?

Xylem

200

What is an ion?

An atom that has lost or gained electrons

200

Why can gases be compressed but solids cannot?

Gases have space between particles; solids do not

200

What is concentration?

Number of particles in a given volume

200

What is the difference between a predator and prey?

A predator hunts and eats other organisms; prey are the organisms that are eaten

300

Why do leaves have many chloroplasts?

To absorb as much light energy as possible

300

What are the products when a metal reacts with an acid?

Salt and hydrogen

300

What type of wave is a sound wave?

Longitudinal wave

300

Describe one way to measure rate of reaction with a gas.

Measure volume of gas produced over time OR change in mass

300

Give one example of competition between organisms.

Plants competing for light, water, or nutrients (or animals competing for food or territory)

400

Explain two ways leaves are adapted for photosynthesis (other than chloroplasts)

Thin → short diffusion distance
Stomata → allow gas exchange
Veins → transport water
Waxy cuticle → reduces water loss

400

Explain why reactivity increases down Group 1.

Outer electron is further from nucleus and less strongly attracted, so it is lost more easily

400

Describe two differences between light and sound waves.

  • Light is transverse; sound is longitudinal
  • Light travels through a vacuum; sound cannot
  • Light is faster than sound 
400

Explain why increasing temperature increases rate.

Particles have more kinetic energy → move faster → more frequent and successful collisions

400

Why do scientists use classification systems?

To organise organisms into groups based on similarities, making them easier to identify and study

500

Explain how light intensity, carbon dioxide concentration, and temperature affect photosynthesis.

  • Light intensity: increases rate because more energy available
  • Carbon dioxide: increases rate as more reactant available
  • Temperature: increases rate up to optimum as enzymes work faster
500

Write word equations for how Magnesium, zinc, and copper react with hydrochloric acid.

  • Magnesium + hydrochloric acid → magnesium chloride + hydrogen
  • Zinc + hydrochloric acid → zinc chloride + hydrogen
  • Copper → no reaction
500

What is the change of state when a solid changes directly into a gas?

sublimation

500

Explain effects of concentration, temperature, and surface area, on the rate of reaction

  • Concentration: more particles → more collisions → faster rate
  • Temperature: particles move faster → more successful collisions
  • Surface area: more exposed particles → more collisions
500

A population of insects in a woodland decreases significantly.
Explain how this could affect:

  • predators
  • plants
  • competing species
  • Predators: decrease due to less food
  • Plants: increase because fewer insects are eating them
  • Competing species: increase as there is less competition for resources