Elements vs Compounds
Is the following an element or compound? Al2
Element
What elements are in the following chemical formula: 3KMnO4?
Potassium, Manganese, Oxygen
Is the following an aqueous solution: Acetic acid can be dissolved in water to form a solution for cleaning. Why or why not?
Yes, because it is dissolved in water.
True or False: Table salt, sugar, and baking soda are all examples of solutes that dissolve in water.
True
Give an example of a physical change.
Boiling water, dissolving sugar in water, etc.
Is the following an element or compound? CaCO3
Compound
How many atoms are in the following chemical formula: CH4?
5 atoms
Is the following an aqueous solution: Several different substances are dissolved in acetone in order to form nail polish remover. Why or why not?
No, because it is dissolved in acetone.
True or False: A soluble solid will dissolve more slowly in hot water than cold water.
False
Give an example of a chemical change.
Burning wood, corroding metal, tarnishing silver, etc.
What elements are in the following compound? H2SO4
Hydrogen, Sulphur, Oxygen
How many molecules and total atoms are in the following formula: 2 MgCl2?
2 molecules and 6 total atoms
Identify the solute and solvent in the following example: Coffee compounds dissolve in water in order to form a solution of coffee to drink.
Solute: Coffee compounds
Solvent: Water
Temperature, Surface Area, or Agitation: Crushing a sugar cube before putting it into water.
Surface area
What is the difference between a physical and chemical property?
Physical properties can be observed without changing the substance, whereas chemical properties will change the substance.
Why are elements not able to be broken down into simpler substances?
Elements are pure substances that consist of only one type of atom, so they are not able to be broken down chemically or physically.
How many total molecules and total atoms are in the following formula: 3 NaClO?
3 molecules and 9 atoms
Identify the solute and solvent in the following example: Certain fats can be dissolved in ethanol.
Solute: fats
Solvent: Ethanol
Temperature, surface area, Agitation: Shaking a container of salt and water will cause the salt to dissolve faster.
Agitation
List 1 physical property and 1 chemical property of gasoline.
Smell and combustibility.
Why are the properties of a compound different than the elements that make it up?
A compound has become a new substance after elements have been chemically combined, therefore it no longer has the same properties as the elements that make it up.
How many total elements, molecules, and total atoms are in the following chemical formula: 2 Al(OH)3
3 elements (Aluminum, Oxygen, Hydrogen), 2 molecules, 14 total atoms
Briefly describe how you can make a solution more concentrated.
You can make a solution more concentrated if you add more solute. Adding more solute will increase the ratio of solute to solvent which makes the solution more concentrated.
Explain three methods of increasing the rate of dissolution of a sugar cube in water.
Increase surface area, temperature, and agitation
How does a physical change differ from a chemical change?
A physical change involves a change in the physical properties of a substance and does not alter its chemical composition. A chemical change involves a change in the chemical composition of a substance which results in the formation of new substances.