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||a) physical, quantitative
|b) physical, quantitative
|c) physical, qualitative
- water is changing state from liquid to gas
- propane reacts with oxygen in the air to produce carbon dioxide and water
- iron oxide was produced
- The sugars in the apple have reacted with the oxygen in the air to produce
new and different molecules which are brown in colour.
- if the tea is evaporated we get the sugar back
- the egg proteins have denatured with the heat and taken on new shapes
- the butter has just changed state from solid and liquid
- the wood molecules react with the oxygen in the air to produce carbon dioxide
- the copper molecules have changed position, nothing else has taken place
chemical - the vaporized candle molecules have burned to produce carbon dioxide
physical - the water molecules in snow melt from solid to liquid, a change
||a) An element
is considered to be the a group of atoms of all the same type. A compound
is considered to be a grouping of molecules of all the same type.
Examples of elements are Gold, Silver, Iron, Chlorine gas, while examples
of compounds are water, NaCl, CO2 and NH4NO3
|b) The solute
is the substance that dissolves when a solution is created while the solvent
is the substance that does the dissolving. The solute makes up the
smaller percentage of the solution while the solvent makes up the larger
percentage. In a solution of salt water the salt makes up the solute
and the water makes up the solvent.
|c) A mechanical
mixture is a mixture that has distinct phases that can be seen after mixing.
A example would be a mixture of salt, sand and sawdust. Even after
mixing the three substances can be seen clearly. A solution is a mixture
in which one substance disappears and so the entire solution displays only
1 phase. An example is sugar and water. Once the
sugar is dissolved the solution shows only the water phase.
A homogeneous mixture is one that displays only one phase, examples being
sugar and water, milk, and cough syrup. A heterogeneous
mixture is one in which two or more phases can be seen after mixing has taken
A proton is a positively charged sub atomic particle found in the nucleus
of an atom. The neutron is a neutral particle also found in the nucleus
of the atom.
A metal is usually a solid with silvery-greyish colours (the exceptions are
gold and silver) which are malleable, good conductors of heat and electricity.
A non-metal can be a brittle solid, gas or liquid and they
are poor conductors of heat and electricity
|g) A atom
is a lone particle of an element. A molecule is the smallest part of
|h) The atomic number (Z) is the number of protons in the nucleus and the number of electrons in orbit in an atom. The mass number (A) is a mathematical sum of the protons and neutrons in the nucleus..|
A pure substance can be either an element or compound that is made up of
100% with nothing else added to it. i.e. Pure gold must have no atoms
other than gold in the sample. A mixture is something that
has more than one type of atom or compound mixed together.
- All the molecules are made from identical atoms. This could be hydrogen,
fluorine, chlorine, oxygen or nitrogen.
- All the molecules are identical.
- All the molecules are identical
- There are two different types of in this diagram. The green atoms
represent a monoatomic element like one of the noble gases and the purple
compound is a diatomic molecule of the element like hydrogen.
- two different diatomic elements
mixture - two diatomic elements and one compound
mixture - one diatomic element and two different compounds
mixture - a monatomic atom and a compound
halogens - fluorine, chlorine, bromine, iodine, astatine
alkali metals - hydrogen, lithium, sodium, potassium, rubidium, cesium, francium
noble gases - helium, neon, argon, krypton, xenon, radon
alkaline earth metals - beryllium, magnesium, calcium, strontium, barium,
||a) The elements in column A are metals
|b) The elements in column B are non-metals
|c) calcium oxide, CaO; potassium fluoride,
KF; aluminium nitride, AlN
||a) The individual components of this mixture
can be separated from each other by using knowledge of their different physical
properties. Sand and iron filings are solid; whereas rubbing alcohol
and water are both liquids. This mixture can be passed through filter
paper. The sand and iron filings will remain in the filter paper, and
the alcohol-water mixture will pass through it. The water that remains
mixed with the sand and iron filings will eventually evaporate. Since
iron filings are magnetic, where as sand is not, the iron filings can be
separated from the sand using a magnet. For the liquid components,
the alcohol has a lower boiling point so the mixture can be heated and the
alcohol will evaporate out of the mixture first leaving behind the water.
|b) mixture, magnet, paper towel, filter
paper, large beaker, distillation apparatus, funnel, iron clamp, retort stand,
Bunsen burner, 10-mL graduated cylinder, round-bottomed flask
Part A: Removal of Sand and Iron Filings from Liquid
1. Pour the mixture through the filter paper. Collect the liquid flowing through the filter paper into a large beaker.
2. Remove the sand and iron filings from the filter paper onto a paper towel.
3. Pour the collected liquid through the filter paper a second time. Collect any additional sand and iron filings caught in the filter paper and add it to the pile on the paper towel. Allow the pile to dry.
Part B: Removal of Iron Filings
4. Use a baggy covered magnet to collect the iron filings from the pile of sand and iron filings on the paper towel.
5. Pull the baggy off the magnet, dropping the iron filings onto a clean paper towel.
6. Repeat until all the iron filings are removed from the sand.
Part C: Separation of the Alcohol and Water
7. Pour the liquid from the large beaker into a round-bottomed flask
8. After setting up the distillation apparatus, turn the water on to fill the condenser tube.
9. Light the bunsen burner and place it under the round-bottomed flask
10. When the temperature reaches approximately 78oC, the alcohol will start to boil. At this temperature, the distillate is alcohol.
11. Collect the distillate at the end of the condenser tube into a 10 mL graduated flask.
12. Stop collecting the distillate when the temperature has reached 82oC
||Distribute the gas into three tubes. To determine
whether the gas is hydrogen, invert the first tube and place a burning splint
just inside its mouth. If you hear a popping sound, the gas is hydrogen.
To determine whether the gas is oxygen, invert the second tube and
place a glowing splint just inside its mouth. If the splint ignites,
the gas is oxygen. To determine whether the gas is carbon dioxide,
pour limewater into the third test tube. Shake well. If a white
precipitate forms, the gas is carbon dioxide.
||a) This action is unsafe. The student
may cut herself with the broken glass through the paper towel. the
broken glass may be coated with toxic or corrosive chemicals. Also,
the student may not be able to collect all the pieces of broken glass with
a paper towel, leaving behind an unsafe work area for other students. The
student should have obtained a brush and a dustpan from the teacher to collect
the broken glass. The broken glass should have been placed in the container
designated "Broken Glass" in the classroom.
|b) This action is unsafe. Rubbing
one's eyes does not remove the chemical, but further distributes it and allows
it to be further absorbed by the eye, resulting in more irritation and damage.
The student should have proceeded immediately to the eye wash station
and flushed the eye with water for 10-15 minutes.
|c) This action is safe.
|d) This action is unsafe. The substances
ingested may be poisonous. No chemicals should ever be ingested in
a chemistry laboratory.
||a) compressed gas
|b) flammable and combustible materials
|c) corrosive materials