Chemistry Module 5

_____ are substances that produce protons when they dissolve in water

Acids

_____ are substances that can accept protons after dissociation in water

Bases

Free hydrogen ions (protons) in water quickly attach to water molecules to become __________ ions

hydronium

______ acids have two H+, which dissociate one at a time

Diprotic

A substance that can act as an acid or a base is described as _________

amphoteric

The numeric value of the water dissociation, Kw, constant is ___________

1.0 x 10⁻¹⁴ at 25°C

A solution with a pH below 7.0 can be described as ______

acidic

A _____________ maintains the pH of a solution by neutralizing small amounts of acid or base

buffer solution

An ________________ is a compound which dramatically changes color when the pH of a solution changes during a titration

acid-base indicator

True or False

Gamma radiation is low energy and can be stopped by clothing or a sheet of notebook paper

False

True or False

During alpha decay, an alpha particle is released to lower the energy of a nucleus

True

True or False

A positron is a positively charged proton found in an electric field

False

True or False

A radioisotope is a specific type of isotope that will instantly decay only when exposed to radio waves

False

True or False

Half-life is defined as the amount of time it takes one-half of a sample of an element to decay

True

True or False

Nuclear fusion is the process by which unstable atoms split releasing energy

False

True or False

Nuclear chain reactions are started by having neutrons collide with materials like Uranium-235

True

True or False

In nuclear fission, two small nuclei join to make a larger nucleus

False

True or False

High doses of gamma radiation will turn you into a superhero

False

What is the difference between an Arrhenius Acid and a Bronsted-Lowry Acid?

No difference

What is the difference between a strong acid and a weak acid?

Strong acids are less likely to reassociate because they split

Does the strength of an acid have any relationship to how reactive it may be in a solution?

No

Write a balanced equation which shows hydrochloric acid dissociating in solution

HCl + H₂O = Cl^- + H₃O⁺

pH Scale

• We use this to talk about how concentrated an acid is

• Scale goes from 0-14

pH equation

-log(H₃O⁺)

Strong acid/base reaction

• reaction yields salt and water, salt being an ionic compound

• strong acid+strong base = salt+water

• H₂SO₄+Ca(OH₂) = CaSO₄+2H₂O

• Ka>1

Acid and carbonate/bicarbonate reaction

• “science volcano” reaction

• reaction yields salt, water and CO₂

• water + CO₂ from carbonic acid

• acid+carb/bicarb = salt+water+CO₂

• 2H₃COOH+Na₂CO₃ = 2NaHCOO+H₂CO₃

Metal and acid reaction

• metal + acid = hydrogen gas + salt

• Mg + 2HCl = H₂(g) + MgCl₂

Arrhenius acid

donates H⁺ in solution

Arrhenius base

donates OH^- in solution

monoprotic

HCl, HNO₃

diprotic

H₂SO₄

triptrotic

H₃PO₄

nuclear chemistry

due to movement of protons and/or neutrons

atomic number (Z)

number of protons

mass number (A)

number of protons and neutrons

isotopes

elements can have different number of neutrons

radioisotopes

unstable species that will split to form a more stable nucleus

radioactivity

• nuclear radiation emitted to “claim” nucleus

• all protons in close proximity become unstable because they all have a positive charge

• as elements get larger, more neutrons are needed to keep distance between the protons

Alpha Decay (α)

• high energy particles

• contains two neutrons and two protons

• written ⁴₂He

• relatively low energy

Beta Decay (β)

• high energy electrons

• results from neutron becoming proton

• written ⁰_-1e

Position Decay (β⁺)

• antimatter particle

• proton becomes a neutron

• written ⁰₊₁e

Gamma Decay (γ)

• high energy release

• no actual particle is released

• written ⁰₀γ

half life

• the amount of time it takes for 50% of a material to undergo it’s decay

• can be on the order of seconds or thousands of years

nuclear fission

• splitting an atom to get energy

• nuclear reactions work by this on Earth

nuclear fusion

• joining two atoms to get energy

• how stars work; small atoms are slammed together to make a bigger one

Blood pH

7.36-7.42