Lab Practices
Can you eat or drink in the lab?
No
What is chemistry?
Chemistry is the study of the properties and behavior of matter.
How many significant figures does the number 100? 0.01?
1 significant figure in each
What are the three states of matter?
Solid, liquid, and gas
What is the charge of a proton, neutron, and electron respectively?
Proton: +1
Neutron: 0
Electron: -1
What are three things you should wear/not wear for a lab?
Wear: protective eyewear, gloves, close toed shoes, long hear tied back
Not wear: open toed shoes, long baggy sleeves
What is matter?
Matter is anything that has mass and takes up space. Everything is made up of matter.
Write 1.2345 with only four significant figures
1.235
What is true of the shape and volume of gasses?
They have neither a definite shape nor a definite volume?
What is an ion? What is the name of a positive ion? A negative one?
A charged particle. A negative ion is an anion, a positive ion is a cation.
In the event of broken glass, what should you do?
Notify the teacher immediately and do not pick up the glass!
Accuracy: Agreement of a particular value with the true value
Precision: Degree of agreement among several measurements of the same quantity
Find 1.03 x 12.500 x 0.4321 to the correct number of significant figures
5.56
How do molecules behave in solids, liquids, and gasses?
Solid: particles are packed tightly together, only vibrate gently
Liquids: Particles move around one another, move slightly faster
Gas: particles are spread apart and move fast
What is an atomic number? What is a mass number?
Atomic number: the number of protons in the nucleus of one atom of the element
Mass number: the number of protons + neutrons in one atom of the element
What are four examples of units in this class (specifically, the metric system)?
Celsius, grams, kilograms, meters, centimeters, etc (teacher's digression)
What is the difference between an atom, an element, and a compound?
Atom - the building blocks of matter
Element - made up of unique kinds of atoms. one element contains the same type of atom
Compound - made up of two or more elements bonded together
Find 5.500000 + 8.340 to the correct number of significant figures
13.840
What would we call Sil4
silicon tetraioxide
What would we get if we combine N3- and SN4+ (remember that the cation goes first, and the anion goes second)
Sn3N34
How should you read a meniscus?
What is the difference between a physical change and a chemical change? What is an example of each?
Physical change - a change in matter that does NOT change the composition of a substance. Examples are changes in state (from solids to liquids to gasses), temperature, and volume
Chemical change - results in a new substance. Examples include combustion, oxidation, and decomposition
When rounding for significant figures, at what point in your calculations do you round?
ie: you have three beakers. One measures to 3 significant figures, one to 2, one to 4. Do you add their measurements from 2 significant figures from the beginning? Do you round at the end?
You round at the end! Only round the final answer to allow for the most precise calculation possible.
Write the formula for the following molecular compound: Boron tribromide
BBr3
Determine the number of protons, electrons, and neutrons in a 3- ion of N-53
Protons: 7
Electrons: 10
Neutrons: 46