Science exam

What is an ionic compound

Complete transfer of an electron to make a full outer shell

Compound

A substance formed when two or more elements are chemically bonded together.

Ion

An atom or molecule that has gained or lost one or more electrons, resulting in a net electric charge.

Covalent Bond

A type of chemical bond that involves the sharing of electrons between elements of similar valency to form a full outer shell

Catalyst

A substance that increases the rate of a chemical reaction without undergoing any permanent chemical change.

Exothermic Reaction

A chemical reaction that releases heat energy to its surroundings. (heat outwards, increase in temp)

Endothermic Reaction

A chemical reaction that absorbs heat energy from its surroundings. (heat inwards, decrease in temp)

What is a cation

A positively charged ion (loses electrons)

Anion

negatively charged ion (gains electrons)

What is the mass number

Protons and neutrons

What is the atomic number

number of protons

Define decomposition

When the reactant seperates to form the products

Define precipitation

When two soluble reactants form an insoluble product

Define combustion

Burning of fuels or metals to produce either CO2 + H20 or light and heat

Distance vs displacement

Distance is scalar -- how much ground an object has covered

Displacement is vector -- The change in position of an object (distance + direction)

Velocity vs speed

Velocity- vector (measures speed AND direction), rate an object changes it position

Speed- scalar, rate an object is travelling at (how fast)

Weight vs mass

Mass is the quantity of matter of the object (scalar)

Weight is the force of gravity upon that quantity (N) (vector)

Define acceleration

Change in speed over a period of time

Scalar vs vector quantities

Scalars have only magnitude; vectors have both magnitude and direction.

Examples of contact forces

friction, applied, and normal

Examples of non-contact forces

Gravity, magnetic, electric

Define Newton's 3 laws

1. Inertia -- object at rest stays at rest

2. F=ma -- if force increases, accel. increases, but if mass increases, accel decreases

3. Equal and opposite reaction

Define the law of falling bodies

All objects fall at the same rate in a vacuum chamber because they are not affected by gravity (force)

Define an energy transfer

Physical movement of energy

Define an energy transformation

A change from one form of energy to another (chemical change)

DNA

Deoxyribonucleic acid, the carrier of genetic information which codes for inherited characteristics and protein production

Gene

Sequence of DNA that codes for a protein and thus determines a trait (regions of DNA made up of sequences)

Chromosome

A threadlike structure made up of tightly coiled DNA around histones, found inside cells

Genome

All the genetic information in an organism

Genotype

An organism's genetic makeup

Phenotype

The observable/expressed characteristics of an organism-what's visible

What makes a nucleotide

sugar, phosphate, nitrogenous base

What are the complementary base pairings

Adenine, Thymine, Cytosine, Guanine

Heterozygous

An organism that has two different alleles for a trait

Homozygous

An organism that has two identical alleles for a trait

What is a mutation?

A permanent change in the DNA sequence of an organism

What is the purpose of mitosis

Repair and growth

What is the purpose of meiosis

Reproduction

How many daughter cells are produced in mitosis

2 (diploid)

How many daughter cells are produced in meiosis

4 (Haploid)

What is Mendelian inheritance

Inheritance pattern of genes that segregate and assort independently

Where does meiosis occur?

Sex cells

Where does mitosis occur?

all over the cells in an organism

What are some causes of genetic variation

Meiosis, mutations, fertilisation/reproduction

How does natural selection + isolation lead to changes in species

Adaptations to different conditions

Evidence for the theory of evolution

Comparative anatomy, biochemical analysis, fossil record, transitional fossils, selective breeding

What makes up a polymer

monomers/sequences/chains of monomers

Causes of environmental pollution

Plastic production, littering etc

Why is there so much plastic in the ocean

Because it isn't biodegradable (well, is over 1000 years)

How to reduce the impact of plastic

recycling, reusing, paper products rather than plastic

What is thermosetting

A type of plastic that can not be re-moulded—not biodegradable

What are thermoplastics

a type of plastic that is recyclable—can be remelted and moulded many times

What are plastics

Synthetic carbon-based compounds