Week 5 Quiz: Chemical Reactions

Which one of the equations below is most likely correct?

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How many Hydrogen atoms are in the reactants of the reaction show below.

• 2

• 4

• 6

• 8

How many Hydrogen atoms are in the products of the reaction show below.

• 2

• 4

• 6

• 8

Which statement best describes what happens to atoms in a chemical reaction?

• New atoms are created which become products

• Some atoms disappear while others multiply to become the products

• The atoms of the reactants rearrange to become the products

• The atoms of the reactants are transformed into different types of atoms which become the products

Atoms are conserved during a chemical reaction. Pick the statement that best describes what it means for atoms to be conserved in a chemical reaction.

• The reactants and products have the same # of atoms but different types of atoms

• The reactants and products have the same type of atoms but different numbers of atoms

• The reactants and products have the same number and same type of atoms

• The reactants always have less atoms than the products

In the chemical reaction show below the reactants are shown on the left side of the equation and the products are shown on the right. If you count the atoms in the reactants there are:

• 4 carbon atoms, 2 oxygen atoms, and 4 hydrogen atoms

• 1 carbon atoms, 2 oxygen atoms, and 4 hydrogen atoms

• 1 carbon atoms, 4 oxygen atoms, and 4 hydrogen atoms

• 4 carbon atoms, 4 oxygen atoms, and 4 hydrogen atoms

In a chemical reaction ...

• The reactants & products have different atoms but the same properties

• The reactants & products have the same atoms but different properties

• The reactants & products have different atoms and different properties

• The reactants & products have the same atoms and the same properties

A student makes a ball-and-stick model of a propane molecule, as shown below. The black balls represent carbon atoms, and the white balls represent hydrogen atoms.

Based on the model, what is the chemical formula of propane?

• $C_3H_8$

• $C_3H_{10_{ }}$

• $3CH$

• $3CH_8$

 If the reactants of a chemical reaction are $C_3H_8+5O_2$ the products must have what number and type of atoms? 

• 1 Carbon atom, 1 Hydrogen atom, 5 Oxygen atoms

• 3 Carbon atoms, 8 Hydrogen atoms, 5 Oxygen atoms

• 3 Carbon atoms, 8 Hydrogen atoms, 2 Oxygen atoms

• 3 Carbon atoms, 8 Hydrogen atoms, 10 Oxygen atoms

Which picture properly represents the arrangement of the atoms present as the products of the reaction shown.

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