Rusting of an iron nail is
Question 1
Rusting of an iron nail is an example of a change of phase.
True/False
Question 2
Which of the following amounts is closest to the molar mass of C18H25NO?
1.9419 kg
200 g
128.44 g
1.30 lbs
Question 3
Occasionally an asteroid will break into fragments due to a collision. These fragments, which often contain ice, can leave the asteroid belt and even make their way to Earth. Upon entering the Earth’s atmosphere, such a fragment is heated to high temperature by frictional forces. Ice contained within a fragment typically liquefies or vaporizes. This type of change is considered a chemical change.
True/ False
Question 4
The following chemical equation is not balanced: A + R2 ? A2R3. After balancing, this chemical equation is ____ .
4A + 3R2 ? 2A2R3
2A + R2 ? A2R3
A4 + R6 ? A4R6
A2 + R3 ? A2R3
Question 5
Burning gasoline is an example of a physical change.
True/False
Question 6
During a chemical reaction, atoms in the reactants rearrange their chemical bonds to make products. The new arrangement of bonds does not have the same total energy as the bonds in the reactants. Therefore, when chemical reactions occur, _____
energy is always released.
there will never be an accompanying energy change. Any change would violate the law of energy conservation.
energy is always absorbed.
there will always be an accompanying energy change.
Question 7
Which of the following does not affect the rate of a reaction?
molar mass
surface area
temperature
catalyst
Question 8
Given the following reaction: N2H4 ? 2H2 + N2, how many moles of H2 will be produced if 3.10 moles of N2H4 react?
Only enter your numerical answer below – do not include units. Report your answer to 2 decimal places.
Question 9
How many moles of caffeine are there in 378.0 g of caffeine?
Only enter your numerical answer below – do not include units. Report your answer to 2 decimal places.
Question 10
41.0 grams of F2 react according to the following balanced chemical equation: F2 + 2NaI ? I2 + 2NaF. As a result of this reaction _____ grams of I2 are produced.
Only enter your numerical answer below – do not include units. Report your answer to 2 decimal places.
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