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Grade 8 Chemistry

Released Test Items

QuestionAnswer
Several centuries ago, men called alchemists tried to transform common metals into gold. Even though they tried many different chemical and physical methods, they never succeeded because... Elements cannot be changed to other elements by physical or chemical means.
Which of the following molecules does not contain three atoms? N2
A substance made up of two or more elements that have been chemically combined is called... A compound
A solution may be prepared by dissolving crystals of a salt in water. Which of the following would probably not affect the rate of solubility? Reducing the air pressure on the solution.
A compound is a molecule made up of atoms from at least two elements. Which of the following gases is a compound? Methane (CH4)
A proton has which of the following charges? Positive
Which of the following materials is composed of only one kind of atom? Helium
Which picture illustrates the structure of a molecule of water? H \ O / H
Mercury is a liquid metal that is used in many thermometers. The mercury in the thermometer rises because it... Expands when heated.
Which of these best shows that calcium is different from all other elements? Its number of protons.
In a experiment combining vinegar and baking soda, gas is given off. In this chemical reaction, the vinegar and baking soda are... Reactants.
Which of these cannot be separated into its parts by an ordinary chemical or physical process? An atom of carbon (C)
The atom is composed of electrons, protons, and neutrons. What is the electric charge on the neutron? 0
Compounds are made up of more than one element. Which of the following represents a compound? NH3
Calcium metal (Ca) can be produced by passing an electric current through molten calcium chloride (Ca12). Chlorine gas (C12) is also formed. What is the balanced equation for this reaction? CaCl2->__Ca+Cl2
Which of these belongs in the outermost shell (energy level) of an atom? Electrons.
When plants perform photosynthesis, they use sunlight to produce food. This is an example of light energy being converted to... Chemical Energy.
Created by: taylor.oconnell
 

 



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