Unit 2 Flashcards
What is scientific notation?
A way of expressing really big or small numbers
What are the parts of scientific notation?
- A number between 1 and 10
Multiplied by - A power of 10 (10^x)
Define accuracy
You end up with the intended value
Define precision
Consistency
How do you determine dig figs when adding or subtracting?
Place value/decimal places
How do you determine dig figs after multiplying or dividing?
Fewest total sig figs
What is temperature?
The measure of the kinetic energy of the atoms/molecules in an object
What tools do we use to measure temperature?
Bulb thermometer
Digital thermometer
Turkey popper
Galileo thermometer
What is the unit of measurement for temperature?
Degrees or kelvins
Kelvin symbol and water freezing and boiling points
K
273 K
373 K
Celsius symbol and water freezing and boiling points
°C
0°C
100°C
Fahrenheit symbol and water freezing and boiling points
°F
32°F
212°F
Why is Kelvin important?
Kinetic energy is never negative, so Kelvin was created as an appropriate scale that gives a more accurate representation of what temperature really is.
What is energy?
The capacity to do work or to produce heat
What are the types of energy?
Potential
Kinetic
Radiant
What are the 3 units of measurement of energy?
Calorie
BTU
Joule
Define calorie
The amount of heat needed to raise 1 gram of water 1° Centigrade
Define BTU
British Thermal Unit
Heat needed to raise 1 lb of water 1°F
Define joule
SI standard unit for energy
Force of one Newton acting through one meter
What is a watt?
Power of a joule of energy per second
Calories in a BTU
252
Joules in a calorie
4.184
What is the law of conservation of energy?
Energy is neither created nor destroyed
What are the 3 different water sterilization methods?
Plasma/uv
Chlorine
Ozone
Pros and cons of plasma/uv sterilization
Fast, no bad taste or smell, easy maintenance, low cost to run
No staying power, expensive equipment
Pros and cons of chlorine sterilization
Cheap, staying power
After taste and smell
Pros and cons of ozone sterilization
No bad taste or smell
No staying power
What is matter?
Everything that has mass and volume
What are the states of matter?
Solids Liquids Gases Plasma Bose Einstein condensate
Solids have:
Definite shape and volume
Close together molecules and very little movement
Liquids have:
Indefinite shape and definite volume
Molecules that have more space between them than a solid does but less than a gas
Gases have:
Indefinite shape and volume
Molecules that move in random patterns with varying amounts of distance between the particles
What is the most common form of matter?
Plasma
Plasma in the _____ and in space makes up over ____% of the visible universe
Stars
99
How does plasma based UV water sterilization kill bacteria?
It disables the DNA of microorganisms in the water. This only takes about 12 seconds
Plasma based uv water treatment systems use about _____ times less energy than boiling water
20,000
Changing states requires:
Energy in the form of heat
What is a physical change?
When a substance changes state but doesn’t change its chemical composition. The appearance has changed but the properties have not.
What is a chemical change?
When a substance changes into a new substance through a chemical reaction. Properties, like density and boiling and melting points, change
What are common signs of a chemical change?
Bubbles forming, change in mass
What is a physical property?
Properties that can be observed or measured. We can determine them without changing the identity of the substance
What are chemical properties?
The way a substance can change or react to form other substances
What is the law of conservation of matter?
Matter cannot be created nor destroyed. It is just converted from one form to another.
What are intensive properties?
Properties that don’t depend on the size of the sample of the matter, like density, color, and boiling point.
What are extensive properties?
Properties that depend on the quantity of the sample, like mass and volume.
What are the 3 types of substances?
Element
Compound
Mixture (not a pure substance)
Characteristics of pure substances:
Fixed composition
Cannot be separated into simpler substances by physical methods
Can only change properties by chemical methods
Properties do not vary
What is a pure substance?
Compounds: can be decomposed into simpler substances by chemical changes, always in a definite ratio
Or
Elements: cannot be decomposed into simpler substances by chemical changes, basic building block of matter
What is a substance?
A substance cannot be further broken down/purified by physical means. Has its own unique properties.
What is a mixture?
Two or more substances that are not chemically combined. Don’t have constant boiling and melting points.
Characteristics of mixture:
Variable composition
Components retain their properties
May be separated into pure substances by physical methods
What are homogeneous mixtures?
Look the same throughout but can be separated by physical means. Components are indistinguishable.
What are heterogeneous mixtures?
Composed of relatively large pieces that can be seen and easily separated
What are solutions?
Solutions are homogeneous mixtures when something is completely dissolved in something else
What are colloids?
Colloids are solutions in which one substance is trapped inside another substance. Can be identified by how they scatter light, like fog.
