What is Chemistry?/ Measurement
Give a definition of chemistry.
The study of matter and how it interacts with itself and energy.
Classify if the properties are physical or chemical.
1. Flammability
2. Volume
3. Length
4. Reactivity
5. Density
6. Odor
7. Acidity
1. Chemical 2. Physical 3. Physical
4. Chemical 5. Physical 6. Physical
7. Chemical
What is the smallest unit of matter? Would it be matter if you broke that unit down further? Explain.
Atoms, Not really, would be subatomic particles which doesn't really exist on its own; would be looking to find a nucleus (nuclear attraction).
What is the atomic number for:
Silver
Os
Xe
47
76
54
Difference between a cation and anion? Give an example of both.
Cation= positively charged, lost electron
Anion= negatively charged, gained electron
Determine in the number of significant figures in the value: 15.039010
7
Determine if the following changes are chemical or physical.
1. Ripping paper
2. Dissolving Salt in water
3. Mold growing on bread
4. "Volcano" experiment (vinegar + baking soda)
5. Digestion
1. Physical
2. Physical
3. Chemical
4. Chemical
5. Chemical
Describe the structure of an atom using subatomic particles.
Dense nucleus with protons and neutrons. Electrons in electron cloud outside of the nucleus in orbitals.
How many neutrons do the following elements have?
Be
O
I
5
8
74
How many valence electrons does each element have? What do you think the atoms will do?
1. N
2. Kr
3. K
1. 5 valence, gain 3
2. 8 valence, nothing
3. 1 valence, lose 1
A student is asked to measure exactly 0.512g of NaCl (sodium chloride = salt) without using a scale. They got the following measurements:
0.555g, 0.517g, 0.410g, and 0.3912g
Were they accurate? Precise? Both Neither?
Neither.
Accuracy is how close you are to the target (0.512g).
Precision is how repeatable your measurements are (Are you getting measurements around the same number?)
What is the difference between a physical and chemical change?
Physical change does not change the chemical composition of the substance. Substances keep their properties (for the most part)
Chemical change causes a change to the chemical composition. Substance's properties generally change and cannot be reversed easily.
Describe the following as either an element, compound, or mixture.
1. chocolate chip cookie,
2. Titanium
3. Carbon Dioxide
4. Water
5. Lemonade
1. Mixture
2. Element
3. Compound
4. Compound
5. Mixture
Describe what happened to each ion.
F-
Mg 2+
O2-
Gained 1 electron
Lost 2 electrons
Gained 2 electrons
What is the octet rule? What does that mean for the atom?
Tendency to exist with 8 electrons in the valence (outer shell); get electron configuration close to a noble gas config.
Joshua uses his thermometer and finds the boiling point of ethyl alcohol to be 75.0°C. He looks i a reference book and finds that the actual boiling point of ethyl alcohol is 80.0°C. What is his percent error?
(measured - real) / real x 100
6.3%
What are the states of matter?
Solid, liquid, gas, plasma, BEC
What is the difference between a compound and a mixture?
Compound: fixed ratio, usually "chemically mixed"
Mixture: Not a fixed ratio, physically mixed.
Give any three element families, and give one example element from each family.
See periodic table.
Draw a lewis dot diagram for P.
Draw it!
Convert 18.95 mL to hL
0.0001895
Prove that you are made of Matter.
You are have mass, take up space.
An atom has 50 protons. Which element is it?
Somehow it then gains another PROTON, what element is it?
Sn- Tin
Sb- Antimony
Calculate the average atomic weight for carbon.
mass % abundance
12 98.93
13 1.07
(Mass x abundance) + (Mass x abundance)
Round to significant figures!
12.0 amu
Electron configuration for Iron
1s22s22p63s23p64s23d6
[Ar] 3d6 4s2