2nd Quarter CRT Test Bank

8th Grade Mobile County Public Schools

2006 - 2007

Question / Answers
What type of reaction occurs when the baking powder is mixed with water and carbon dioxide gas is produced? / Chemical reaction
Give examples of physical reactions? / Ice melting
What is a shorthand description of a chemical reaction using chemical formulas and symbols called? / Chemical equation
Where do the reactants and products appear in a chemical equation? / Reactants before the arrow, products after the arrow.
What are the starting materials in a chemical reaction? / reactants
What are the substances formed from a chemical reaction? / products
What separates the formulas of the reactants from the formulas of the products? / Yield sign
Given chemical equations, be able to balance them. / Al2O3→Al + O2
Count atoms of oxygen in a chemical formula. /
Identify subscripts in a chemical equation. /
According to the law of conservation of mass, how does the mass of the products compare to the mass of the reactants? / The mass is always equal
Identify the number of atoms in a chemical formula: / C
What are numbers in front of the symbols and formulas called? / coefficient
In which type of reaction do ions in two compounds switch places? / Double replacement
Given a chemical equation, determine the type of chemical reaction. / 2 H2O ---> 2 H2 + O2
What kind of reaction occurs when two or more substances combine to form a single compound? / synthesis
What kind of reaction occurs when a single compound breaks down to form two or more simpler substances? / decomposition
What kind of reaction occurs when an element takes the place of another element that is part of a compound? / Single replacement
What is a decomposition reaction? / A single compound is broken down into simpler substances.
What is a compound considered to be when only a FEW molecules of a compound break apart in water to produce hydrogen ions? / Weak acid
What type of compound increases the number of hydroxide ions when dissolves in water? / base
What type of compound produces MANY hydroxide ions? / Strong base
What kind of acid or base is formed when FEW molecules of a compound break apart in water to produce hydroxide ions? / Weak base
What happens when acids react with bases? / They neutralize each other
What pH does a solution have if it is neutral? / 7.0
How would you describe human blood with a pH of between 7.38 and 7.42? / Slightly basic
What type of soil with a pH between 4 and 6, do some plants, such as pine trees prefer? / Acidic soil
Why might people add a base to an acidic lake? / To neutralize the acid
Identify the acid in a reaction: / HCL
Identify a base in a reaction: / KOH
What is the process by which substances move from areas of higher concentration to areas of lower concentration? / diffusion
One gram of salt is dissolved in one liter of water creating a salt water solution. What is the water portion of the solution called? / solvent
What is the universal solvent? / water
What would happen to a cell in a hypotonic solution? / It would shrink
What is the substance being dissolved in a solution? / solute
What is a compound that increases the number of hydrogen ions when dissolved in water? / an acid
What is a compound considered to be when ALL the molecules of a compound break apart in water to produce hydrogen ions? / strong acid
How can you increase the amount of table sugar that will dissolve in 1 liter of water? / stirring the solution or increasing the temperature of water
How can you increase the amount of oxygen that will dissolve in 100g of water? / increase the pressure of oxygen
How could a sugar cube be dissolved more quickly in water? / crush the sugar cube
Why can salt dissolve in water? / salt is soluble
What forms when particles of two or more substances are evenly mixed? / solution
What is formed when particles of two or more substances are distributed evenly among each other? / solution
Which state of matter does not change shape in different containers? / solids
What is added or removed to water to cause a change state? / energy
What is the temperature at which a substance changes from a solid to a liquid called? / melting point
What is the temperature at which a liquid changes into a solid called? / freezing point
The freezing point is the same temperature as which other point during a phase change? / melting
What is the term used to describe changing from a liquid to a gas? / boiling
What process does water redeposit into a lake in the form of rain? / vaporization
Why does water form on the outside of a glass of cold lemonade? / condensation
What is a chemical reaction in which energy is released or removed? / exothermic
What is a chemical reaction in which energy is absorbed? / endothermic
What happens to the reaction rate when reactant particles collide more often? / the reaction rate increases
If given samples of baking soda in a powder, small cube, and small crystal form, which would react the fastest with vinegar? / powder
What is a substance that speeds up a reaction without being permanently changed called ? / a catalyst
What is a substance that slows down or stops a chemical reaction called? / an inhibitor