Lab Safety
What constitutes protective gear for labs?
Gloves, protective eye wear, lab coat. This can also include close-toed shoes
How do you calculate percentage error?
[(experimental value - accepted value) x 100]
What is a balance used for?
To find the weight of a substance
What would you categorize an unknown substance as if it cannot be separated into separate components?
A homogenous mixture
Which equation below corresponds to direct and indirect proportionality
y = x
y = 1/x
Direct : y=x
Indirect: y=1/x
What is the most important rule of lab safety?
Read and understand all instructions before the lab begins
What are the correct units for Volume and Density?
Volume: m^3
Density: kg/m^3
Why would you use a graduated cylinder?
To measure the volume of liquids
If a pure substance can be broken down by ordinary chemical means, what is it?
A compound
What are the four ratings on the MSDA (NFPA Diamond Chart)
- Health Hazard
- Fire Hazard
- Specific Hazard
- Instability (Reactivity)
How many meters are in 5,020 kilometers
5.020E6
What would you use a pipette for?
Dripping small amounts of liquid
If an unknown substance cannot be separated, what type of matter is it?
A Pure Substance
What should you do if glass is broken
Let the teacher know and stand clear of the area until the mess is cleaned (by the teacher)
What are the proper SI units and symbols for the following measurements:
Length, Mass, Time, Temperature
Length = l = meter (m)
Mass = m = kilogram (kg)
Time = t = seconds (s)
Temperature = T = Celsius (C) or Kelvin (K)
What would use an Erlenmeyer Flask for?
To heat or mix substances
Extensive vs. Intensive Property
Extensive - depend on a sample size (ex: volume, mass, and size)
Intensive - do not depend on the quantity of matter (ex: density, state of matter, and temperature)
If smelling a substance is necessary, how should you smell it?
Waft the item from the equipment it is held in to your nose.
What are the conversion factors for the following:
- kilo
- deci
- centi
- milli
- micro
- kilo: 10^3
- deci: 10^-1
-centi: 10^-2
-milli: 10^-3
- micro: 10^-6
What would you use a beaker for?
Used to hold substances or measuring the volume of a liquid
Define a physical and chemical change
Physical - a change made to a substance that results in the same substance
Chemical - a change made to a substance that results in a different substance/substances