Topic 3 States of matter separating and purifying Flashcards
1 What are the three states of matter?
solid, liquid, gas
2 In which state are the particles arranged regularly?
solid
3 In which state do particles move quickly in all directions?
gas
4 What state change happens when a substance melts?
solid to liquid
5 What state change happens when a substance condenses?
gas to liquid
6 In general, which state of matter has particles with the highest energy?
gas
7 What is the melting point of water in °C?
0 oC
8 What is the boiling point of water in °C?
100 oC
9 When a substance is melted, is energy transferred to or from the surroundings?
from (The substance gains energy from the surroundsing)
10 The melting point of sodium is 97.7 °C. What is the state of sodium at 25.0 °C?
solid (The temperature is below the melting point, so it hasnt yet melted!)
11 Gold is a pure substance. T or F?
true (although you can get alloys of gold which are mixtures and not pure substances)
12 Air is a mixture. T or F?
true (it is mixture mostly of the elements Nitrogen (N2) and Oxygen (O2))
13 Carbon dioxide is a mixture. T or F?
false (it is a compound of carbon and oxygen)
14 Pure substances only have one type of atom present T or F?
false (you can get pure compounds e.g. you can get pure salt, NaCl)
15 All mixtures are made up of compounds. T or F?
false (you can get a mixture of elements, for example air)
16 Pure substances have a sharp melting temperature. T or F?
true (as opposed to mixtures which melt over a temperature range)
17 A metal alloy is likely to melt over a range of temperatures. T or F?
true (because it is a mixture)
18 The temperature changes as a pure substance melts. T or F?
false (the temperatue stays constant as the energy is used to change state (break bonds))
19 When a substance melts, its particles move around and become less ordered. T or F?
true
20 A heating curve with an upward sloping gradient during melting indicates a pure substance is present. T or F?
false (for a pure substance the heating curve is flat during a state change)
21 What is a mixture?
different elements and/or compounds that are not chemically joined together
22 Which is a mixture, air or water or both?
air (as long as the water is pure water)
23 Which of a ‘mixture’ or a ‘pure substance’ has a fixed composition?
pure substance
24 Name a pure substance.
any suitable e.g. gold, salt, water can all be pure