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1. Science 10 > Unit A Energy and Matter in Chemical Change : Section 1.0 > Flashcards

Unit A Energy and Matter in Chemical Change : Section 1.0 Flashcards

1
Q

What does WHMIS stand for?

A

Workplace Hazardous Materials Information System

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2
Q

What is MSDS?

A

Material Safety Data Sheet

Identifies physical and chemical hazards associated with a product

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3
Q

Generally, what do Physical Properties describe?

A

They describe the physical appearance and composition of a substance

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4
Q

What are the common Physical properties

A
  • Boiling point
  • Melting point
  • Freezing point
  • Malleability
  • Ductility
  • Colour
  • State
  • Solubility
  • Crystal formation
  • Conductivity
  • magnetism
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5
Q

Generally, what do Chemical properties describe?

A

The reactivity of a substance

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6
Q

What are the common chemical properties?

A
  • Ability to burn
  • Flash point
  • Behaviour in air
  • Reaction in water
  • Reaction with acids
  • Reaction with heat
  • Reaction to litmus paer
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7
Q

What is a flash point?

A

Temperature needed to ignite a flame

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8
Q

What happens if a substance undergoes a physical change?

A

It still has all the same properties and is reversible

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9
Q

What happens if a substance undergoes a chemical change?

A

A new substance is formed and it is irreversible

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10
Q

What are the two classifications of matter? Define both.

A

Pure substance: matter that has definite composition

Mixture: combinations of matter that can be separated by physical means; do not have definite composition

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11
Q

What is a pure substance?

A

All the particles that make up the substance are chemically combined and identical; they have definite composition (atoms within are in fixed proportions due to their bonds to one another)

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12
Q

What are the two types of pure substances? Define both.

A

Element: cannot be chemically broken down into simpler substances

Compound: two or more elements that are chemically combined; can be separated chemically into simpler substances

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13
Q

What is an element?

A

A pure substance that cannot be broken down chemically into other substances and made of only one type of atom

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14
Q

What is a compound?

A

An group of elements that are chemically combined in fixed proportions

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15
Q

What is a mixture?

A

A combination of matter that can be separated by physical means. Proportions of one pure substance to another making the the mixture can vary.

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16
Q

Mixtures can be heterogeneous or homogeneous:

What is a mechanical mixture / heterogeneous mixture?

A

When the different components are visible such as soil

The composition of the material is variable throughout the mixture

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17
Q

What is a suspension?

A

A type of heterogeneous mixture where the components are in different states such as mud

Mud or muddy water: where soil, clay, or silt particles are suspended in water.

Flour suspended in water.

Kimchi suspended on vinegar.

Chalk suspended in water.

Sand suspended in water.

Suspensions have larger particles than colloids so they separate eventually. Colloids stay mixed for longer because the particles are so tiny. Solutions on the other hand are homogeneous mixtures held together by charges and the idea of dissolving.

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18
Q

What is a colloid?

A

A type of heterogeneous mixture, mix of two different states, but the particles cannot be easily separated since they are tiny in comparison to a suspension.

Colloids include fog and clouds (liquid particles in a gas), milk (solid particles in a liquid), and butter (solid particles in a solid). Other colloids are used industrially as catalysts. Unlike in a suspension, the particles in a colloid do not separate into two phases on standing. Keep in mind that milk will only separate into butter and liquid when it is spun so fast that the particles are forced to separate. Thus milk is a colloid because it does not turn into butter on its own.

Do not confuse a colloid with a solution. A solution is due to dissolving a solute in a solvent. A solution is a homogenous mixture that is held together with charges from ions.

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19
Q

What is a Solution (also known as a homogeneous mixture)?

A

One substance dissolved within another but it looks the same throughout.

The composition is the same throughout the mixture.

Different components are not visible.

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20
Q

What is a chemical reaction?

A

A process that occurs when substances react to create different substances or a different substance

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21
Q

What are some ways to preserve food?

A

Heating
Dehydrating
Freezing
Salting
Canning
Fermenting
Smoking
Cold storing (root cellars to store root vegetables)

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22
Q

What is Sterilization?

A

Any process that kills micro-organisms

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23
Q

How does freezing sterilize food?

A

The low temperature prevents the growth of micro-organisms that cause decay

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24
Q

How does salting sterilize food?

A

The salt draws the water out of the meat and the bacteria. The bacteria either cannot live or are inactivated without water.

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25
Q

How does fermentation work?

A

The lactobacilli creates lactic acid which is a preservative. It prevents the growth of bacteria that causes food to rot

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26
Q

What are lactobacilli?

A

Bacteria found in food that that convert starches and sugars into lactic acid

27
Q

What are the positives to lactobacilli?

A
  • Preserves food
  • Increase vitamin levels
  • Makes food digestible
28
Q

How does smoking preserve food?

A

Introduces antioxidants and formaldehyde to slow the rotting process

29
Q

What are the 3 ages of metal?

A
  • Copper
  • Bronze
  • Iron
30
Q

Why was copper a good metal?

A

It was harder, so it could be used to make tools and weapons, and jewelry.

31
Q

What is Native Copper?

A

Copper found in the arctic ocean that is found in pure form.

32
Q

What did the early Inuit use copper for?

A
  • Handles
  • Pots
  • Staples
  • Rivets
33
Q

What was the problem with copper?

A

When they hammered it into shapes it became too brittle and broke easily.

34
Q

How did they solve the copper problem?

A

By melting it to strengthen it

35
Q

What is annealing?

A

The heating of a metal before shaping it

36
Q

What is smelting?

A

Separating metal by melting it

37
Q

What was a positive to smelting?

A

Things were hard to find in pure substances, BUT with smelting metals found in mixtures could be separated

38
Q

What did Aristotle believe about matter?

A

It was made from earth, fire, water, and air

39
Q

Who came up with the idea of atoms?

A

Democritus

40
Q

What is alchemy?

A

A combination of science and magic

41
Q

What did Robert Boyle discover?

A

By experimenting with volume and gas he concluded that gasses are made up of tiny particles

42
Q

What did Antoine Lavoisier Discover?

A

The law of Conservation of mass

43
Q

How did Antoine Lavoisier discover the Law of Conservation of Mass?

A

He measured masses of substances that reacted together and the substances created. He discovered that mass is neither produced nor lost in a chemical reaction

44
Q

What did John Dalton discover?

A

The billiard ball model of Atoms. He imagined they were small spheres that could have different properties and varied in size color and mass

Dalton’s Atomic Theory
• All matter is made up of small particles called atoms.
• Atoms cannot be created, destroyed, or divided into smaller particles.
• All atoms of the same element are identical in mass and size, but they
are different in mass and size from the atoms of other elements.

45
Q

Describe John Dalton’s atom

A

The Billiard Ball

  • All matter is made of small indivisible particles
  • All atoms of an element are identical in properties such as size and mass
  • Atoms of different elements have different properties
  • Atoms of different elements could combine in specific fixed ratios
46
Q

What did J.J. Thomson add onto John Daltons Atom?

A

He added electrons

In 1894, English physicist J. J. Thomson (1856–1940) used a new version
of the gas discharge tube to obtain direct evidence that cathode rays were actually
a stream of negatively charged particles. Thomson’s modified gas discharge tube
used charged plates to bend cathode rays around a curved path. He knew that
by measuring the radius of their path, he could calculate information about
the mass and charge of the particles.

The electrons in this model are like raisins in a plum pudding or raisin bun.
Thus, Thomson’s theory has been called the “plum-pudding” or “raisin-bun”
theory. This model (also called the Thomson atom) could not account for
a phenomenon that Thomson himself was studying. Radioactive elements
had only recently been isolated in pure form. They appeared to be constantly
emitting fast-moving, positively charged particles. These particles are called
alpha particles and have about 7200 times the mass of an electron. The Thomson
atom contained nothing similar to alpha particles, and gave no clues about how
they might be formed.

47
Q

What did J.J. Thomson discover?

A

The electron

48
Q

How did J.J. Thomson discover the electron?

A

He was experimenting with beams of particles produced in a vacuum. And they all turned out to be negative which means they all had something in common: the electrons

49
Q

Who created the raisin bun model?

A

J.J. Thomson

50
Q

Describe J.J. Thomsons model of the atom

A

The raisin bun model was a positive sphere with electrons embedded within it

51
Q

What did Ernest Rutherford change about J.J. Thomson’s atom model?

A

He said that the core of the atom was called a nucleus and it was positively charged and negative electrons were floating around the nucleus but not in a specific direction

In 1909, New Zealand-born physicist Ernest Rutherford (1871–1937) designed
an elegant experiment to probe the structure of atoms. As shown in Figure 1.12
on the next page, Rutherford’s apparatus directed a stream of alpha particles
from a shielded sample of radioactive polonium toward a very thin gold foil.
Collisions with gold atoms, or parts of gold atoms, in the foil were expected
to cause the alpha particles to change direction slightly and hit different parts
of a fluorescent screen placed near the foil. Rutherford observed this deflection.
He observed something else, as well. A small number of alpha particles bounced
back from the gold foil.

52
Q

Who was the first scientist to use the term nucleus?

A

Ernest Rutherford

A nucleus: a central region that is positively charged,
extremely small, and yet contains almost all of the atom’s
mass. Such a nucleus would be far too dense to be a cloud
or shell of positive charge, as Thomson had suggested.
Rather, Rutherford visualized the nucleus as containing
tiny, relatively massive particles, each with a single
positive charge — protons

53
Q

What experiment did Rutherford use to determine his atom?

A

Gold foil experiment:
He released a radioactive material that fired positively at gold and he assumed the they would pass right through but instead, they were deflected which meant they had a strong positive charge

54
Q

Describe Ernest Rutherfords atom?

A

It had a dense positively charged nucleus and around it was mostly empty space with electrons floating around

Hydrogen is the element with the least-massive atoms. Rutherford hypothesized
that hydrogen would have the simplest possible atom: one proton and one
electron. It seemed logical that helium, the next-lightest element, would have
two protons and two electrons. That would make a helium atom twice as
massive as a hydrogen atom. According to experimental evidence, however,
helium atoms are four times more massive than hydrogen atoms.
To explain these results, Rutherford hypothesized that there was a third
subatomic particle in the atom. He hypothesized that this particle had the
same mass as the proton, but no electrical charge. For this reason, he called
the particle a neutron. A helium atom, then, would contain two protons and
two neutrons (as well as two electrons), making it four times as massive as a
hydrogen atom.

55
Q

What did Neils Bohr discover about rutherfords atom?

A

He said that electrons surround the nucleus at different energy levels, therefore, they travel in orbits.

According to physical theory, electrons moving around a
nucleus should constantly emit energy in the form of light or radio waves. This
process would cause the electrons to spiral into the nucleus, and the atom would
collapse. Atoms, however, do not collapse. There is also no evidence that their
electrons emit energy under normal conditions.
In a gas discharge tube, however, gases do emit light, but only when electrical
energy is supplied to them. As well, each element emits specific colours of light.
These colours are different for each element. The colours of light correspond to specific wavelengths. This means that the colours have different energies.
Rutherford’s atomic theory had no explanation for this behaviour.

56
Q

What did Neils Bohr notice in order to conclude that electrons travel in orbits?

A

He discovered that different lights are emitted when electrons are from different energy levels

  • each element emits specific colours of light.
    These combinations of different colours are different for each element. The colours of light correspond
    to specific wavelengths. This means that the colours have different energies. For example, there are missing colours on one element compared to the next as seen when you split the light rays into a rainbow.
57
Q

Who was the scientist that discovered how electrons flow in orbits?

A

Neils Bohr

58
Q

What was Neils Bohr’s description of atoms?

A

They had a positively charged nucleus and electrions orbited in specific energy levels

Energies could be thought of as electron shells or energy levels. Electrons would be associated with specific energy levels. In addition, electrons could move only from one allowed energy level to another

59
Q

Describe the Quantam Mechanics Atom

A

Electrons are thought of as a cloud of negative charges and occupy the whole space at the same time at different electricity levels

60
Q

What is bronze made out of?

A

Copper and tin

61
Q

How did they make bronze?

A

They smelted copper and tin together and the metal produced was much stronger

62
Q

How did the Iron age begin?

A

They realized that Iron could be found in mineral compounds so they were able to smelt it out. Just like Copper

63
Q

What is matter?

A

Anything with mass and volume
Can be solid, liquid, or gas

64
Q

What is nuclear notation?

A

The atomic mass number, also known as mass number, (total amount of neutrons and protons) is listed upper left.
The atomic number (amount of protons) is listed lower left.
The element symbol is listed to the right.

1. Science 10 (13 decks)

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