Topic 2-Chemistry

Question 1

What is an isotope

Answer 1

Same element, different number of neutrons

Question 2

Explain carbon dating

Answer 2

Because certain isotopes of carbon are radioactive, it under goes radioactive decay. Scientist compare the amount of carbon in an object to how much there should be and use it’s half life to calculate how old it is

Question 3

Describe ionic bonds

Answer 3

A bond where one atom takes another atoms electrons in order to have a full shell.

Question 4

What is an ion

Answer 4

When a atom or molecule has a charge that isn’t 0 because it either gained or lost an electron

Question 5

What are covalent bonds? Polar covalent? Non polar covalent?

Answer 5

Covalent bonds are when two atoms share electrons. Non polar is when the electrons spend equal time between the atoms. Polar is when one of the atoms has a stronger electronegativity and pulls the electrons towards it more.

Question 6

What creates polar bonds? What type of atoms often create toolbar bonds?

Answer 6

Inequalities in electronegativity. The higher the electronegativity the stronger the pull. Mismatches in electronegativity create polar bonds. Carbon and hydrogen are low strength, nitrogen and oxygen are high strength.

Question 7

What are dipoles?

Answer 7

When an molecule has positive and negative charged sides due to polar bonds

Question 8

Describe hydrogen bonds

Answer 8

Weak bonds between positive and negative dipoles. Often hydrogen atoms and other polar molecules

Question 9

List and describe the properties of water

Answer 9

1. Density- when water is solid, it is less dense than liquid form. Because in solid form water molecules are moving slow enough to create all 4 polar bonds which allows the molecules to move farther apart and create a vacuum of space between the molecules increasing the vol.
2. Adhesion- water sticks to anything polar or charged. Because it wants to for h bonds
3. Cohesion- water sticks to itself
4. Heat capacity- it requires more energy to heat I kilo of water 1 degree C because it takes a lot of energy to keep breaking hydrogen bonds
5. Solvent of life- everything can be dissolved in water because it sticks to and surrounds anything polar or charged

Question 10

What causes a solution to become more acidic? Less Acidic? How is this represented on the Ph scale

Answer 10

It is more acidic when the concentration of hydrogen ions is higher than hydroxide, lower ph. More basic when there is a higher concentration of hydroxide ions than hydrogen ions, higher ph number