Honors Chemistry Study Guide - Semester 1

Unit 01 - Introduction to Chemistry

Unit 01 - Introduction to Chemistry

What is Chemistry?

Study of how one type of stuff is transformed into another type of stuff w/ different properties

How do transformations happen in Chemistry?

Transformations are done through the making and breaking of chemical bonds

What are the 5 main branches of chemistry?

• Organic Chemistry

• Physical Chemistry

• Analytical Chemistry

• Biochemistry

• Inorganic Chemistry

1st step to scientific method?

The first step of the scientific method is to find a problem you want to solve or a purpose.

2nd step to scientific method?

You then form a hypothesis about your problem, and what you think will happen.

3rd step to scientific method?

Conduct an experiment in order to test out your hypothesis.

4th step to scientific method?

Collect the data you gathered from your experiment and analyze it to come to a conclusion.

5th step to scientific method?

Draw a conclusion based on if your hypothesis was correct, but also what you learned from the experiment.

What is the difference between dependent and independent variables?

• The independent variable is the ONLY variable that changes

• The dependent variable is the data that’s measured to compare the results of your tests; what you are observing

What is a control in an experiment?

• a specific group or baseline used for comparison of your results

• sometimes the normal or regular state/condition

What is a theory?

explanation of how something happens and why things happen

How is a theory different from a law in science?

A theory explains how and why things happen, while laws are simple statements that tell you what will happen

What are the two types of research performed by scientists and how are they different?

• Pure research is for fun and for the sake of knowledge, there isn’t really a defined purpose

• Applied research is done when there’s a problem to solve and scientists look to find new solutions

Unit 02 - Data Analysis

Unit 02 - Data Analysis

What are SI units and which units that are used in chemistry are considered base SI units?

• SI units are the international system scientists use for units

• seconds (s), meters (m), kilograms (kg), kelvin (K), and mole (mol)

What are the properties and units for these base units?

• seconds (s) — time

• meters (m) — distance and length

• kilograms (kg) — mass

• kelvin (K) — temperature

• mole (mol) — amount of substances (particles)

What are derived units?

All other units that are not base units are derived from the 7 base units

What are some examples of derived units?

• Liters (L)

• Density (g/mL)

How do you calculate temperature in Kelvin?

T_K = T_C + 273

How do you calculate density with correct units?

Density = mass (grams) / volume (mL)

How do we convert units in chemistry? What are the steps?

check notes

What are commonly used prefixes in the metric system (ex: milli) and what values do they refer to?

• Mega (M) = 10⁶ (one million)

• Kilo (K) = 10³ (one thousand)

• Centi (C) = 10^-2 (one hundredth)

• Mili (m) = 10^-3 (one thousandth)

• Micro (µ)/(mu) 10^-6 (one millionth)

• Nano (n) = 10^-9 (one billionth

What is the difference between accuracy and precision?

• Accuracy: a measure of how close your measured values is to the actual value

• Precision: a measure of how reproducible a bunch of repeated measurements are

What are significant figures?

The digits that matter in a measurement or calculation

What are the rules for determining significant figures?

• Any non zero digit is 100% a significant figure

• Zeros between nonzero digits are significant figures

• When there’s a decimal, zeros after a nonzero digits to the RIGHT are significant figures

• Zeros that are placeholders are NOT significant figures

• Zeros at the beginning of numbers w/ a decimal are NOT significant figures

What are the rules for writing calculated answers when using significant figures?

• If adding/subtracting, answers are rounded to the least significant decimal place

• If multiplying/dividing, answers are rounded to the number w/ the least number of sig figs in a calculation

Unit 03 - Elements and Properties

Unit 03 - Elements and Properties

What are substances?

Matter that is consistent and has an unchanging composition

What are some examples of physical properties of matter?

• color

• mass

• density

• odor

• taste

What are some examples of chemical properties of matter?

• Iron rusting (iron oxide forms)

• gasoline burning (water and carbon dioxide form)

• milk souring (sour tasting lactic acid is made)

What is the difference between physical and chemical changes?

• Physical change: A change that alters a substance w/o changing it’s composition

• Chemical change: A process involving 1 or more substances that change into new substances (Chemical rxn)

What are the different states of matter?

Solid, liquid, gas, plasma

How does volume and shape relate to each state of matter?

• Solids have fixed shapes and volumes (tightly packed, fixed particles)

• Liquids have fixed volumes but take container shapes (particles move around but stay close)

• Gases have neither fixed shape nor volume (particles move more freely and are far apart)

What is the law of conservation of mass?

Mass is neither created or destroyed during a chemical reaction

Why is the law of conservation of mass important?

Matter can change form through physical & chemical changes, but the amount of matter stays the same

What are mixtures?

A combination of 2 or more pure substances while keeping its chemical properties

What is a homogeneous mixture?

Homogenous Mixture

• Mixture that has constant composition

• Always in a single phase

• Called “solutions”

What is a heterogeneous mixture?

Heterogenous Mixture

• Mixtures that don’t blend smoothly

• Individual substance remain distinct

  • Italian dressing, milk

What are elements?

Pure substances that contain only one type of atom

How are elements written?

Written as uppercase letters first, followed by only lowercase letters

What is the definition of a compound?

Combination of 2 or more different elements that are combined chemically

What is the law of definite proportions?

Compounds always have elements in definite proportions by fixed ratios; compounds will always have the same formula and the formula will never randomly switch up

Unit 04 - Atomic Models

Unit 04 - Atomic Models

What did the greeks contribute to our understanding of the atom?

Proposed that matter was made of particles that could not be cut up any further (Leucippus and Democritus)

Who are the early scientists involved in the discoveries that lead us to the modern conception of the structure of the atom?

John Dalton, Eugen Goldstein, Ernest Rutherford

How was the electron discovered?

J.J Thomson used a cathode ray tube to study atoms and saw that there were smaller charged particles; electrons

How was the nucleus discovered?

Ernest shot particles at a thin gold sheet, observing most pass through but a few deflected, revealing a tiny, dense, positively charged center; the nucleus atom

Which scientist discussed in the lecture contributed to our current understanding of the structure of the atom?

How do the masses of electrons, protons, and neutrons compare?

What is atomic number

What is mass number?

How can you determine the mass and atomic number using the periodic table?

How do you label an atomic symbol to represent the atomic number and mass number?

What are isotopes?

How does percent abundance of isotopes affect the atomic weight of an element?

How is atomic mass determined for elements that contains isotopes?

What were contributions to atomic theory of other scientists you learned of in your project?

Unit 05 - Electrons in Atoms

Unit 05 - Electrons in Atoms

What is electromagnetic radiation?

How are wavelength and frequency linked?

What is the speed of light?

What types of radiation make up the electromagnetic spectrum?

What is the order of the types of electromagnetic radiation in terms of lowest to highest wavelength?

What is the order of the types of electromagnetic radiation in terms of lowest to highest energy>

Which are the most dangerous electromagnetic waves?

How do you calculate wavelength or frequency?

What is Planck’s equation?

What is Planck’s equation used for?

How do you convert a wavelength into nanometers (nm)?

What is Hertz (Hz)?

How do you convert between scientific notation and decimal form (standard notation)?

Who was Niels Bohr?

What was his theory of electrons in an atom?

What part of his theory of electrons was not correct?

What evidence for energy levels was discovered and how is the visible light spectrum part of this discovery?

What does it mean when an atom’s electrons are in the ground state or in the excited state?