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Science Year 9 > Chemistry Test 1 > Flashcards

Chemistry Test 1 Flashcards

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1
Q

What is nuclear decay?

A

When a nucleus undergoes a nuclear reaction and emits radiation.

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2
Q

When had a nuclear reaction occurred?

A

When the amount of protons changes and the atom, therefore, becomes another element.

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3
Q

What’s transmutation?

A

When an atom converts into another element.

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4
Q

Why are chemical reactions not nuclear reaction?

A

Because it doesn’t concern the nucleus, only the electrons so it can’t affect the number of protons which changes the element into another.

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5
Q

What are radioisotopes?

A

Isotopes of an element with an unstable nucleus.

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6
Q

What are carbon’s 3 naturally occurring isotopes?

A

Carbon-12, carbon-13 and carbon-14

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7
Q

Which isotope of carbon is radioactive?

A

Carbon-14

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8
Q

What are the 3 types of nuclear decay?

A

Alpha, beta and gamma

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9
Q

What occurs in alpha decay?

A

A nucleus ejects an alpha particle (identical to a helium nucleus) which is 2 protons and 2 neutrons. It only happens in atoms with very heavy nuclei.

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10
Q

What occurs in beta decay?

A

A neutron is converted into a proton and the nucleus ejects a beta particle identical to an electron.

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11
Q

What occurs in gamma decay?

A

Nucleus emits a gamma ray which is a form of light. Moves at the speed of light

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12
Q

What is meant by half-life?

A

The time it takes for half of the nuclei to decay.

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13
Q

What is carbon dating?

A

The use of the half- life of carbon to determine the age of fossils. While an organism lives, the amount stays the same but after they die they stop absorbing it. The amount left helps to tell how long ago it died.

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14
Q

What is nuclear radiation? Examples

A

Any rays or particles emitted by atomic nuclei. Alpha, beta, gamma

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15
Q

What is the biological effect of radiation?

A

It destroys biological molecules and causes unwanted chemical reactions.

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16
Q

What is ionising radiation?

A

Any form of radiation with the ability to remove electrons from atoms and molecules.

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17
Q

What can happen to cells if they’re exposed to ionising radiation?

A

Die or mutate

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18
Q

What’s cell death by radiation and what can it cause?

A

Ionising radiation enters there cell and destroys biological molecules beyond repair. Can cause radiation burns or sickness

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19
Q

What are some symptoms of radiation sickness?

A

Nausea, vomiting, fever, hair loss and diarrhoea

20
Q

What’s cell mutation?

A

Ionising radiation damages the DNA in a cell which makes it reprogramme and it can turn into a cancer

21
Q

What’s genetic/inherited Mutation?

A

When ionising radiation causes mutation in sperm or ova spcells and the offspring is affected.

22
Q

Properties of alpha radiation

A

Particles are large, heavy and slow, 20x more effective an ionising molecules, can only travel a few cm in air, blocked by paper or dead skin

23
Q

Properties of beta radiation

A

Particles small and faster, penetrates skin deeper than alpha, blocked by plate of aluminium

24
Q

Properties of gamma radiation

A

Can travel through skin, bone and aluminium, speed of light, gamma ray instead of particle, blocked by lead, don’t have mass or charge

25
Q

Medical uses of radiation

A

Radiotherapy to treat cancers (kills cells in tumour and stops them multiplying), x-rays/nuclear imaging

26
Q

Uses of radiation in industry

A

Sterilisation to kill bacteria, to look inside objects, to detect the thickness of metal foils, in some smoke detectors.

27
Q

What is a fission reaction?

A

A large nucleus splits into 2 equally sized nuclei.

28
Q

What’s the most famous fission reaction?

A

Uranium-235 absorbs a neutron, forms highly unstable uranium-236. Splits into krypton-92 and barium-141

29
Q

What’s a fusion reaction?

A

2 small nuclei join together to form one large nucleus.

30
Q

Why are fusion reactions so hard to conduct?

A

Since the small nuclei strongly repel each other, it can only be done in extreme high temperatures of over 100 million degrees C, so it has to be done in mid air.

31
Q

How many known types of atoms are there and how many occur naturally?

A

118 known, 98 occur naturally

32
Q

What are the two ways that atoms can exist in elements and compounds?

A

As single atoms (monatomic) molecules or crystal lattices

33
Q

What’s an element

A

A substance made up of only one type of atom

34
Q

What’s so different about the atoms in carbon?

A

They can form very large molecules (buckyball = 60) also the only non-metallic element that can form crystal lattices.

35
Q

What’s a compound?

A

Substances made up of more than one type of atom

36
Q

Describe an atoms internal structure

A

Protons (+) in nucleus with neutrons(neutral), electrons (-) surround nucleus in a cloud

37
Q

What force makes protons attract to electrons?

A

Electrostatic force

38
Q

What force holds the nucleus together?

A

The nuclear force

39
Q

What’s the atomic number?

A

Number of protons (determines element)

40
Q

What’s the mass number?

A

Protons + neutrons

41
Q

What charge are atoms?

A

Neutral because they have the same amount of protons and electrons.

42
Q

What did Ernest Rutherford fins and how?

A

That the nucleus only takes up a small space and most of atoms are just empty space. He fired helium nuclei at a sheet of gold and some bounced back.

43
Q

What are ions?

A

When atoms lose or gain electrons and become electrically charged.

44
Q

What’s a positive ion called?

A

Cation

45
Q

What’s a negative ion called?

A

Anion (changes name and puts ide on the end)

Science Year 9 (4 decks)

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