Lab Equip and Measurements
What is a hypothesis?
A question or educated guess that attempts to explain why things happen
True or False: all nonzero numbers are significant
True
What's da matter?
Anything that has mass and takes up space
What are the two types of mixtures?
Homogeneous and heterogeneous
What is a balance used for?
Measuring mass of a substance
What is a Theory?
broad generalization that explains why things happen and can be disproven
What is the rule for sig figs when multiplying and dividing?
Use the least precise amount from the calculations
What is the difference between an element, molecule, and a compound?
Element simplest form of matter. Molecules are two or more atoms ( example: O2) Compounds are two or more elements (example: CO2)
Describe a homogeneous mixture
Uniform composition
What are examples of physical properties?
Color, density, solubility, melting/freezing point
What is a Law?
an accepted statement that explains what happens
What is the formula for density and what is the common conversion?
D = m/v
1cm3 = 1mL
What is the difference between intensive and extensive properties?
Intensive is independent of the amount. Extensive is dependent on the amount.
What is the difference between evaporation and distillation?
The ability to capture the evaporated liquid
What is accuracy?
How close measurements are to the actual value
What three pieces of equipment is used to heat reactions?
Beakers, Test tubes, and Erlenmeyer flasks
What is precision?
How close multiple measurements are to each other
What are examples of chemical properties?
Burning something, flammability, acid reactivity, toxicity, corrosiveness
What filtration method should be used for separating oil from a mixture of water and oil
Decantation
Not uniform composition; settles out of solution
What is the best piece of equipment to use to measure the volume of a liquid?
Graduated Clyinder
Name all 5 significant figure rules
1. all nonzero numbers are significant 2. captive zeros are significant 3. leading zeros are never significant 4. trailing zeros are only significant if there is a decimal 5. exact measurements/conversions have infinite significance
Solid: definite shape and volume, low energy.
Liquid: Definite volume not shape, medium energy
Gas: no definite shape or volume. high energy
What is the difference between intramolecular and intermolecular forces?
Intra are the forces inside a molecule, inter is between molecules
How would you separate a mixture of sand, salt, and water?
Filter out sand, evaporate water, left with salt