Chemistry Lecture Notes Review

A collection of flashcards based on lecture notes covering key chemistry concepts.

What is an element?

A substance made up of only one type of atom.

What does an atomic number represent?

The number of protons in the nucleus or electrons in an atom.

What does the mass number represent?

The total number of protons and neutrons in the nucleus.

What is a mixture?

A substance made of more than one type of atom NOT chemically joined together.

What is a compound?

A substance that is made up of two or more atoms chemically joined together.

Name the four ways in which mixtures can be separated.

Filtration, evaporation, chromatography, and distillation.

Why do atoms sometimes gain or lose electrons?

To get a full outer shell.

What is an ion?

A charged particle, formed when an atom either loses or gains electrons.

What is a reactant in a chemical reaction?

A substance used up in a chemical reaction.

What is a product?

A substance made in a chemical reaction.

Name the three ways in which you can tell a reaction has occurred.

Change in colour, change in temperature, or fizzing.

What is an isotope?

A form of an element with the same number of protons but different neutrons.

Where would you find electrons in an atom?

Electron shells (orbits) around the nucleus.

Why do atoms never have an overall charge?

An atom has the same number of protons and electrons.

What is relative atomic mass?

The mass of an ‘average atom’ of that element compared with the mass of an atom of carbon-12.

What does the group number tell us about the elements in that group?

The number of electrons in the outer shell.

What is filtration?

A method of separating an insoluble solid from a liquid.

What is evaporation?

A method of separating a soluble solid from a liquid.

What is chromatography?

A method that separates soluble substances such as dyes or inks.

What is distillation?

A method that separates a mixture of liquids due to differences in boiling points.

What do elements in the same period have in common?

They have the same number of occupied electron shells.

What are group 1 metals also known as?

Alkali metals.

Why does the reactivity of group 1 elements increase down the group?

The outer electron is further away from the nucleus and is more shielded.

Which group has elements that are unreactive?

Group 0.

How do alkali metals react with oxygen?

They form oxides.

How do alkali metals react with water?

They form hydroxides and hydrogen gas.

How do alkali metals react with chlorine?

They form chlorides.

Why are most alkali metals stored in oil?

Because they are very reactive and react with oxygen in the air.

Why do group 7 elements get less reactive as you go down the group?

It becomes more difficult to gain an electron due to more shielding from the nucleus.

What colour are sodium ions in a flame test?

Orange-yellow flame.

What colour are lithium ions in a flame test?

Crimson-red flame.

What colour are potassium ions in a flame test?

Lilac flame.

What colour is bromine at room temperature?

Reddish-brown liquid.

What happens to lithium, sodium, and potassium in air/oxygen?

They tarnish on the freshly cut surface.

What test is used to identify hydrogen gas?

A squeaky pop is observed with a lit splint.

What happens when potassium reacts with water?

It floats, fizzes, moves on the surface, and catches fire with a lilac flame.

What happens when sodium reacts with water?

It floats, fizzes, moves on the surface, and melts into a sphere.

What are group 7 elements also known as?

Halogens.

What colour is iodine at room temperature?

Grey/black solid.

What colour is chlorine at room temperature?

Greenish-yellow gas.

What is a displacement reaction?

A reaction in which a more reactive halogen displaces a less reactive halogen.

What happens when you add silver nitrate to chloride ions?

A white precipitate forms.

What happens when you add silver nitrate to bromide ions?

A cream precipitate forms.

What happens when you add silver nitrate to iodide ions?

A yellow precipitate forms.

What are the uses of chlorine?

Kills bacteria; used in the treatment of water supplies, swimming pool water, and making household cleaners.

What are the uses of iodine?

Kills bacteria; used as an antiseptic following hospital procedures.

What colour would you expect for barium ions in a flame test?

Apple green.

What colour would you expect for calcium ions in a flame test?

Brick red.

Why are noble gases very unreactive?

They have a full outer shell.

What test is used for carbon dioxide?

Lime water turns milky.

What gases are dissolved in rainwater?

Carbon dioxide and oxygen.

What ions does groundwater contain?

Mg2+, Ca2+, Na+, and K+.

How do ions get into groundwater?

From minerals dissolved as water travels through rocks.

What is the definition of a solute?

A chemical which dissolves in a solvent to form a solution.

Name four man-made pollutants that pollute natural water.

Pesticides, fertilizers, household waste, and industrial waste.

What is desalination?

The process of removing salt from sea water to convert it into fresh water.

Name three sources of drinking water.

Rivers, lakes, reservoirs.

State the three ways water is purified.

Sedimentation, filtration, and chlorination.

What happens in the filtration stage of treating water?

Smaller insoluble particles are removed through layers of sand and gravel.

What happens in the sedimentation stage of treating water?

Larger solid particles settle under gravity.

What happens in the chlorination stage of treating water?

It kills bacteria, prevents disease, and makes the water safe to drink.

Why is fluoride added to the water?

To prevent tooth decay.

State three reasons not to add fluorine to water.

Fluorosis, bone cancer, mass medication.

What are the two ways of removing water from seawater?

Distillation and reverse osmosis.

How does distillation separate water and ethanol?

Ethanol has a lower boiling point, so it evaporates first.

What is the boiling point of water?

100°C.

What is a fractionating column used for?

Separating several different liquids.

What two processes are involved in distillation?

Boiling and condensing.

What does saturated mean?

When no more solute can dissolve.

What ions do hard water contain?

Calcium (Ca2+) and magnesium (Mg2+).

What does temporary hard water contain?

Calcium hydrogencarbonate and/or magnesium hydrogencarbonate.

What happens when temporary hard water is boiled?

Hardness is removed, and scale (solid calcium carbonate) is formed.

What is the problem with limescale?

It reduces the efficiency of heating elements and can clog up pipes.

What does permanent hard water contain?

Chlorides and/or sulfates of calcium and magnesium.

How does adding sodium carbonate soften hard water?

It prevents calcium and magnesium ions from bonding to the washing detergent.

What is the inner core of the earth made from?

Mostly iron with some nickel.

What is the outer core made of?

A liquid layer made of iron and nickel.

What is the crust made up of?

A thin layer of solid rock.

What does the mantle consist of?

Semi-molten rock.

What is the lithosphere?

The crust and the upper rigid part of the mantle.

What is Pangaea?

Where land masses on Earth were grouped together in one supercontinent.

What is continental drift?

The movement of tectonic plates a few centimetres per year.

Name three observations that prove continental drift.

Jigsaw edges of continents fit together, similar rocks of the same age, and similar plant and animal fossils found on different continents.

What are convergent boundaries?

Edges of the plates that crumple, forming mountain ranges.

What are divergent boundaries?

Plates that move apart, releasing molten rock (magma) as in a volcano.

What are conservative boundaries?

Plates that slide past one another, neither moving towards nor away from each other.

Which three gases made up the very early atmosphere?

Carbon dioxide, water vapour, and ammonia.

How were the oceans formed?

The surface of the Earth cooled, and the water vapour in the early atmosphere condensed to form oceans.

What has caused the percentage of carbon dioxide in the atmosphere to decrease?

Photosynthesis in plants and the locking of CO2 in limestone and chalk.

How is nitrogen formed in the atmosphere?

Ammonia from volcanoes decomposes upon reaction with oxygen.

What does acid rain cause?

It lowers the pH of lakes and soil, damages buildings made of limestone, and increases the corrosion of metal structures.

What is carbon capture?

It removes CO2 produced by burning fossil fuels before they enter the atmosphere.

What does rate measure?

A change in concentration over a given time.

What is activation energy?

The minimum amount of energy needed to start a reaction.

What factors affect the rate of reaction?

Temperature, concentration, and surface area.

What does a catalyst do?

Speeds up a reaction without being used in the reaction by lowering the activation energy.

What test is used to identify oxygen gas?

A glowing splint re-lights when placed in a jar containing oxygen gas.

What test is used to identify carbon dioxide gas?

Limewater turns milky.

What gas is given off during the thermal decomposition of carbonates?

Carbon dioxide.

What colour does green copper(II) carbonate turn on gentle heating?

Black.