WorksheetsMandala Chemistry
Total questions: 26
Worksheet time: 4hrs 20mins
A water molecule has the chemical formula H2O. This means that the water molecule is made up of
Two hydrogen atoms and one oxygen atom
Two oxygen atoms and one hydrogen atom
Two hydrogen atoms and two oxygen atoms
Two molecules of water
The atoms in a water molecule are held together by covalent bonds. This means that the bonded atoms
Two hydrogen atoms and one oxygen atom
Two oxygen atoms and one hydrogen atom
Two hydrogen atoms and two oxygen atoms
Two molecules of water
The water molecule is a polar molecule. A water molecule is polar because
The electrons are shared equally
Oxygen has a stronger attraction for electrons than hydrogen
It is very cold
Hydrogen atoms have a stronger attraction for electrons than oxygen
The water molecule is ....
Slightly negative near the hydrogen atoms and slightly positive near the oxygen atom
Slightly positive in all areas of the molecule
Slightly negative near the oxygen atom and slightly positive near the hydrogen atoms
The same charge in all areas of the molecule
Water molecules are attracted to each other because....
They are all positively charged
Each water molecule has the same number of protons as electrons
The positive area of one water molecule is attracted to the negative area of another
All water molecules are neutral
If liquid A is more polar than liquid B, you might expect
Liquid A to evaporate faster than liquid B
Liquid A to evaporate more slowly than liquid B
Liquid A and liquid B to evaporate at the same rate
Liquid B to be colored
A paper clip can stay on the surface of a sample of water because of water’s strong surface tension. Water’s surface tension is mostly a result of
Water’s temperature
The motion of water molecules
The attraction of water molecules
The impurities in the water
Sodium chloride is made up of sodium ions and chloride ions which bond together in a salt crystal because
They have the same charge
They are the same size
One is positive and one is negative so they attract
They both have protons and electrons
Water is able to dissolve sodium chloride because
The polar areas of water molecules attract the oppositely charged ions of sodium chloride
The shape of the water molecules pushes the sodium and chloride ions apart
The oxygen in the water molecules reacts with the sodium and chloride ions
Water molecules and sodium chloride are covalently bonded
Water cannot dissolve all substances that are made from ionic bonds. This is probably because
Some water molecules are not as strong as others
Water needs to be stirred to dissolve all ionic substances
Some ionic bonds are too strong for the attractions of water molecules to pull them apart
Water needs to be heated to dissolve all ionic substances
The chemical formula for sucrose (sugar) is C6H12O6. In some parts of the sucrose molecule, oxygen is covalently bonded to hydrogen. This makes the sucrose molecule
Bonded like salt
Smaller than a water molecule
A polar molecule
Act like a liquid
Sucrose dissolves well in water because
Water is usually warm
Sucrose is used to make sweet beverages
Polar water molecules attract the opposite polar areas of the sucrose molecules
Polar water molecules attract the carbon atoms in the sucrose molecules
When sucrose dissolves in water
The sucrose molecules break apart into individual atoms
The water molecules covalently bond to the sucrose molecules
The water molecules cause the sucrose molecules to separate from one another
Each sucrose molecule breaks in half
Alcohol molecules are not as polar as water molecules. If you mixed sucrose in alcohol you might expect the sucrose
To dissolve better in alcohol than in water
To dissolve in alcohol not as well as in water
To dissolve equally well in alcohol and in water
To increase in size
Dissolving often involves a solid dissolved in a liquid. In this type of dissolving
The solid is the solvent
The liquid is the solute
The solid is both the solvent and the solute
The solid is the solute and the liquid is the solvent
The solubility of a substance
Is the solvent minus the solute
Is the mass of the substance plus the mass of water it dissolves in
Has nothing to do with the temperature of the water
Is the mass of a substance that will dissolve in a certain volume of water at a certain temperature
Sugar is more soluble at higher temperatures. This is mainly because at higher temperatures
Sugar and water molecules move slower and their interactions make the sugar molecules stay together longer
Sugar and water molecules move faster and their interactions make the sugar molecules separate from one another
Water molecules spread out more, making more room for the sugar molecules
Water molecules actually come apart into separate atoms and react with the sugar
Water is not a good dissolver of oil mainly because
Oil is also a liquid
Oil is thicker than water
Oil molecules are non-polar
Oil is colder than water
Carbon dioxide gas dissolves pretty well in water because
The molecules of a gas are far apart compared to the molecules of a liquid
The bond between the carbon and oxygen in the carbon dioxide is polar
Water can dissolve anything with carbon
Water molecules are non-polar
The amount of gas that can dissolve in water
Increases as the temperature of the water increases
Increases as the temperature of the water decreases
Does not change when the temperature of the water changes
Does not depend on the type of gas
When certain substances dissolve, the solution gets warmer. This type of dissolving process is exothermic. In exothermic dissolving
More energy is released when water molecules bond to the solute than is used to pull the solute apart.
More energy is used to pull the solute apart than is released when water molecules bond to the solute.
A gas is always produced
The temperature does not change
When certain substances dissolve, the solution gets colder. This type of dissolving process is endothermic. In endothermic dissolving
More energy is released when water molecules bond to the solute than is used to pull the solute apart.
More energy is used to pull the solute apart than is released when water molecules bond to the solute
Water molecules break apart into atoms
The temperature does not change
What does it mean to say that something is a “polar molecule”?
A water molecule (H2O) is polar. This means that it has a slight negative charge near the oxygen atom and a slight positive charge near the hydrogen atoms. Using what you know about covalent bonding in the water molecule, explain why a water molecule is polar.
Sodium chloride (NaCl) is made up of sodium ions (Na+) and Chloride ions (Cl-). Use what you know about polar water molecules to explain why water is able to dissolve salt.
Bonus Question!
If you can answer correctly this questions it will help you to get more 20 point.
How can you predict which solids, liquids, and gases dissolve in water?
