11. What is the difference between an isotope and an ion? (Check all that apply)
isotopes are atoms with extra electrons or too few electrons
ions are atoms with extra electrons or too few electrons
isotopes are atoms with extra neutrons or too few neutrons
ions are atoms with extra neutrons or too few nuetrons
isotopes are radioactive
ions are radioactive
12. Biology is the study of living things. Carbon is the element that makes life possible. Why is carbon so special that it is required for life?
It is a positively charged ion needed in reactions.
It has 4 valence electrons, so it can make 4 strong bonds with other atoms.
It is a polar molecule, which makes it have a high heat capacity.
Because it has 4 valence electrons, it is small and only makes small compounds.
13. Covalent bonds are formed when 2 atoms share electrons. Ionic bonds are formed when one atom steals 1 or more electrons from another atom, creating positive and negative ions. These ions now "stick together". Using the table below, which column of elements are more likely to form ionic bonds than covalent bonds?
Captionless Image
orange and yellow
red and dark purple
orange and blue
red and light purple
14. A compound is a molecule built of 2 or more different elements. How are the properties of the compound related to the properties of the elements that make it?
The compound has different properties, because the bonds cause structural changes of the elements
The compound has the same properties of the atoms, because the properties of elements don't change
The compound has different properties, because the elements stay the same
15. When a chemical reaction occurs, energy is either used up (absorbed) or released (given off). What is the term that describes a reaction in which there is an explosion of heat and light?
endothermic
exothermic
ionic
covalent
16. What are the reactants in the following reaction: CH4 + O2 -------> CO2 + H20 (Check all that apply)
CO2
O2
CH4
H2O
17. The sum of all chemical reactions in a living thing:
homeostasis
metabolism
evolution
photosynthesis
18. A catalyst is anything that speeds up a reaction. In living organisms, the protein that acts as a catalyst is an enzyme. How do enzymes speed up reactions in living things? **Check all that apply
By decreasing the activation energy needed to start the reaction
By bringing the substrates together so the reaction can occur
By increasing the energy that is needed to start the reaction
19. What does the pH scale measure? Check all that apply (1/2 point each).
The amount of protons in a solution.
The temperature of a solution.
The amount of hydrogen ions in a solution
How acidic or basic a solution is
20. Which of the following is a building block of proteins?
monosaccharides
amino acids
lipids
sugar
21. Describe how enzymes affect chemical reactions and explain why this makes enzymes important to living things.
22. List in order the organization of living organisms, starting with the simplest and ending with the most complex.
