Chemistry Unit Test Review
What is an ion?
An ion is an atom or group of atoms that has a positive or negative electric charge.
How do you calculate density?
Density = mass / volume
The Periodic table consists of 18 columns called:
Groups
What are the three main categories of elements on the periodic table?
Metals, Non-metals, Metalloids
CH₄ + O₂ ---------> CO₂ + H₂O Is this a balanced equation?
No
What is the chemical symbol for Oxygen?
O
Protons have a ______________ charge.
positive
What is the difference between mass and weight?
• Mass is the measure of how much matter is in an object. • Weight is the force of gravity on an object.
What are the three ways to find the volume of an object?
• length * width * height • displacement • overflow method
How many molecules are represented by the formula Fe₂O₃?
1
How many different elements are used to make iron oxide (Fe₂O₃)?
2 (Fe and O)
How many atoms are needed to make iron oxide (Fe₂O₃)?
5 (2 Fe and 3 O)
What is the difference between a chemical change and a physical change?
A chemical change is when one substance changes into another substance. The atoms have been re-arranged, and you can only change it back if you break the chemical bonds. Physical changes can be easily changed back to the original.
What is a mixture?
A combination of two or more substances that do not combine chemically but remain the same individual substances.
What is a product?
A substance formed by a chemical reaction.
What is a reactant?
A substance that is present at the beginning of a chemical reaction and is changed into a new substance.
What is an endothermic reaction? Give an example.
Adding heat or energy - Melting, Sublimation, Evaporation
The basic unit of matter is:
An atom
CH₄ + O₂ ---------> CO₂ + H₂O What is the reactant in this equation?
CH₄ + O₂
CH₄ + O₂ ---------> CO₂ + H₂O What is the product in this equation?
CO₂ + H₂O
During the chemical reaction of baking soda and vinegar, bubbles appear. What's in the bubbles?
Carbon Dioxide
Give one example of a chemical change.
Cooking an egg.
What is the chemical symbol for Copper?
Cu
How are elements on the Periodic Table arranged?
Elements on the Periodic Table are arranged by properties and atomic number.
What is the chemical symbol for Iron?
Fe
What is the chemical symbol for Hydrogen?
H
List three things that are not made up of matter and do not have mass:
Light, sound, heat
What is the chemical symbol for Sodium?
Na
If you cut a cube of copper in half, does it change the density? Why or why not?
No, the density does not change.
What does the Law of Conservation of Matter say?
Particles cannot be created or destroyed, only rearranged.
The Periodic table consists of 7 rows called:
Periods
What is an exothermic reaction? Give an example.
Take heat or energy away - Freezing, Deposition,Condensation
What happens to the mass when ice melts in a glass of water?
The mass stays the same.
What happens to the mass when sugar is dissolved in water?
The mass stays the same.
What is a compound?
a substance made up of two or more different types of atoms bonded together.
What is an element?
an element consists of atoms of only one type.
Give one example of a physical change.
cutting paper, melting an aluminum can
Most of the elements on the periodic table are ________________.
metals
Electrons have a ____________ charge.
negative
Neutrons have a ______ charge.
neutral
The atomic number of an element shows the number of __________________ in the nucleus.
protons
The atomic mass number of an element shows the number of _________________ and ___________________ in the nucleus of the atom.
protons and neutrons
In a chemical reaction, what are the similarities between reactants and products?
the mass of the products and reactants are the same - the atoms have just been re-arranged.
A glass marble has a volume of 5 cm³ and a mass of 13 g. What is the density of the glass?
• Density = mass/volume • Density of the glass = 13 g / 5 cm³ • Density of the glass = 2.6 g/ cm³
Explain the difference between the movement of molecules in a solid, liquid and gas state.
• In a solid state, molecules are in fixed positions and are close together. • In a liquid state, molecules are close together, but are freer than those in a solid. • In a gas state, molecules are very far apart, and the amount of space between them can change easily.
