Vocabulary - Week of January 25, 2016 Week 18 – Quiz: Feb 02, 2016
1. Concentration: A measure of how much solute is dissolved in a solvent.
Solutions can be dilute (with a high proportion of the solvent), or
concentrated (with a high proportion of the solute).
2. Conservation of Mass:: Mass can neither be created nor destroyed in a
chemical reaction
3. Fractional distillation: A method of distillation using a fractionating
column, used to separate liquids with different boiling points.
4. Diffusion: The process by which different fluids mix as a result of the
random motions of their particles.
5. Crude oil: Mixture of hydrocarbons, mainly alkanes, formed over millions
of years from the remains of ancient dead marine organisms.
6. Hydrocarbon: compounds that are made up of hydrogen and carbon.
7. Molarity: The number of moles of solute per liter of a solution.
8. Mole: the measure of amount of a substance in chemistry; one mole of a
substance has a mass equal to its relative formula mass in grams – the
amount of substance contains 6.02 x 1023 atoms, molecules or formula
units depending on the substance considered.
9. Reactants: substances present at the start of a chemical reaction
10. Product: the substance formed in a chemical reaction.
H
J
E
F
I
C
D
G
A
B
11. Label the parts of this figure
A
B
Residue
A. ________________________+1
Filtrate
B. ________________________+1
12. How is Filtration useful? +3
Filtration has many uses:
It separates coffee solution from ground up coffee beans.
Oil filters in cars contain material such as cotton, or wood fibre. These
materials trap bits of dirt. Liquid oil passes through gaps between the
fibres. The dirt would damage the engine if it stayed in the oil.
Sand filters help make water safe to drink, removing bacteria, sand, or
tiny creatures.
13. Naomi adds 100 g of different compounds to separate beakers of water,
and stirs to dissolve. Each beaker contains 100 g of water. She filters
each Mixture, and measures the masses of solid that remains. Use the
data to work out the most and least soluble substance. Show your
working. +4
Name of Substance
Calcium chloride
Calcium hydrogen
carbonate
Calcium bromide
Calcium iodide
Mass of Substance
added to 100 g of water
100
100
Mass of residue after
filtering (g)
25
84
100
100
0
33
Amount of solute dissolved in 100g of water:
Calcium chloride = 100 – 25 = 75 g
Calcium hydrogencarbonate = 100 – 84 = 16 g – least soluble
Calcium bromide = 100 g - most soluble
Calcium iodide = 100 – 33 = 67 g
14. Match the sentence starters with their endings: +4
A saturated solution
…does not dissolve
…is the mass of substance that
dissolves in 100g of water
An insoluble substance
Solubility
…is a solution that contains the
greatest mass of solid that can
dissolve
… may contain un-dissolved solid
15. Describe the relationship shown +3
Temperature (°C)
Solubility of Zinc bromide (g/100
g of water)
446
590
616
647
669
20
40
60
80
100
Solubility (g/ 100 g of water)
Solubility of ZnBr2
700
650
600
550
500
450
400
0
20
40
60
80
100
120
Temperature (°C)
The gradient shows that solubility increases with temperature but up to a
limit at approximately 700 g/ 100 g of water.
16. During a laboratory assignment you compared a combining two (2x)
50 cm3 volumes of dried green peas to two a 50 cm3 volume of peas and a
50 cm3 of salt. You noticed the total volumes were different. What was
the difference and how do you explain that difference? +4
The difference was the combination of peas and salt totaled a volume that
was less than the volume of peas alone. This is because the salt, being
smaller than the peas, and the peas being irregularly shaped, the salt was
able to fill the space between peas, which did not add to the total volume
of the mixture.
17. You also mixed 50 cm3 of water and 50 cm3 of ethanol. Were your
observations the same or different than the experiment with salt and
peas? +1
Not the same: Water mixed with ethanol yielded the same total volume as
two volumes of ethanol.
18. What did you expect to see when mixing Water and Ethanol based on the
Bill Nye video shown? +2
I expected that water mixed with ethanol would have a smaller total
volume than ethanol alone.
19. Did your observations (questions 14 and 15) match your expectations?
Why or Why not? [Hint: were the differences in the features of the
experiment? Tap water, for example, is a heterogeneous mixture. What
effect do you think using tap water verses pure water may have?] +3
My observations DID NOT match my expectations in that I expected a
smaller total volume than I got. This may be because the ethanol already
had water mixed with it. So, if the water is to behave like salt, filling space
between the larger molecules of ethanol, then water mixed with the
ethanol would already fill some of the space that additional water would
fill. Also the water we used wasn’t pure water, so contaminants may
affect the results.
20. Salt in Water: You added salt into water, virtually and actually. Drawing
on both experiences describe how salt interacts with water in a solution.
Additionally, draw a diagram. +4
When salt dissolves in water, is breaks apart into sodium and chlorine
atoms. Water molecules surround the individual atoms.
21. Salt in water: Describe what happens after saltwater reaches its
saturation point, and draw a diagram. +4
When saltwater becomes saturated, no more salt can go into solution and
solid salt will precipitate out of solution collecting at the bottom of the
container.
22. Are the following imaged depicting saltwater solutions that are Saturated
or Unsaturated? Circle one: +2
Saturated
Unsaturated
Saturated
Unsaturated
23. You found that 180 molecules of salt is the solubility point for salt in the
simulation in a volume of 5.0 x 10 -23 L. Using this information, explain
how you would calculate the solubility of sodium chloride salt in grams/
Liter. +6
180 molecules of salt
1 mole
58.5 grams
X
X
5.0 x 10-23 L
6.022 x 1023 molecules
1 mole salt
1.75 x 10-20 grams salt
350 grams/ Liter
5.0 x 10-23 L
=
=
24. Does this match the true solubility of salt, which is 359 grams/ Liter +1
Yes
25. You added 60 grams of salt to make a 60 ml solution of salt and water.
What is the concentration in grams/ Liter? +4
60 grams of salt
60 mL
X
1000 mL
1L
=
1000 grams
Liter
26. Should this volume of salt go into solution? +2
No, it is much more than the saturation point of 350 grams/ Liter
27. How can you help to put this volume of salt into solution? +2
Adding heat can help.
28. Mr Joyner measured the boiling points of Water, saltwater, and alcohol
and water. Explain his results: +3
A. Water:
100°C
B. Saltwater:
80°C
C. Alcohol:
70°C
Mixing salt and alcohol with water lowers the boiling point of the
water solution.