1.3 Units and Conversions Flashcards
S.I. Units - system international
* Length = m
* Mass = kg (however, in chemistry we normally use the gram, however the actual base SI unit is the kg)
* Time = s
* Temp = Kelvin (K) - has a true 0, doesnt have negative
* Volume = m^3 - however the L is more commonly used in chemistry (but M^3 is the SI unit)
* Energy/Work = J
* Pressure = Pa (pascale) - however, in chemistry we use atm more
Terra
10^12
Giga
10^9
Mega
10^6
Kilo
10^3
Centi
10^-2
just like cent is 1/100th of a dollar
Milli
10^-3
Micro
10^-6
nano
10^-9
Pico
10^-12
femto
10^-15
atto
10^-18
Convert 75g to mg
use this
equality means
a statement that two expressions or quantities have the same value
basically something like 1000mg = 1g would be an equality
dividing by 10^-3 is the same as multiplying by 10^3
so in this case he multipled the top number by 10^3
1in = 2.54 cm. How many feet is 17.1m
They’re always going to provide a conversion factor to convert metric to american system in the problem. I just have to know how to use it
To figure out sig figs its a little involved than just knowing its multiplication and division so go by least percise. We need to know that we do not look at the conversion factors for the sig figs - this makes sense because those are always going to be infintly percise
so in this problem we only look at 17.1 and see that it has 3 sig figs, so we make our answer have 3 sig figs
How many feet are in a yard
3
Notice: you must cube the entire thing - which gets the units and the numbers which is really important
so the reason we cube the entire thing is because it cubes the units and the numerical value, whereas if we just added the squared on it would only get the units
the below should be 3 sig figs (which it is)
K = C + 273
C = 10 - K = 10 + 273 = 283K
0C = 32F
100C = 212F
This is how to convert back and forth from F to C and C to F
Kelvin is an absolute scaling meaning it has a true 0 that you can’t go beneth
Density equation
* Is density intensive or extensive?
* what greek letter is used to represent this ?
Mass/Volume
Its intensive - meaning that no matter how much of something you have it doesnt change (size doesnt matter)
* think water, no matter how much you have the density of water doesnt change
The two units that make up densisity are extensive though
* Mass = if you have more of something you have more mass
* Volume = if you have more water in the pool you have more volume
* However, these two are essentially in a ratio when divided meaning that density is uninpacted by the size of something
p (row) is used to represent density
What is the density of this cube?
how to solve for density
Which ever one has the prefix (in this case Micrograms has the prefix micro while grams doesnt have a prefix). So the one with the prefix gets the number 1
the base unit (in this case grams) uses the table and gets the power of 10
He litteraly just counted it out instead of putting it in a calculator
This is the way I should be doing these. Convert to grams then convert grams to any of the units. Way easier than whatever flipping way hes doing it.
3200g
The key was knowing that the density was the same becsuse they’re made out of the same plastic (and size of the cube doesnt imapct density because its a ratio)
high relability (or percision)
