Answer:
1.21 g of Tris
Explanation:
Our solution if made of a solute named Tris
Molecular weight of Tris is 121 g/mol
[Tris] = 100 mM
This is the concentration of solution:
(100 mmoles of Tris in 1 mL of solution) . 1000
Notice that mM = M . 1000 We convert from mM to M
100 mM . 1 M / 1000 mM = 0.1 M
M = molarity (moles of solute in 1 L of solution, or mmoles of solute in 1 mL of solution). Let's determine the mmoles of Tris
0.1 M = mmoles of Tris / 100 mL
mmoles of Tris = 100 mL . 0.1 M → 10 mmoles
We convert mmoles to moles → 10 mmol . 1mol / 1000mmoles = 0.010 mol
And now we determine the mass of solute, by molecular weight
0.010 mol . 121 g /mol = 1.21 g
Greetings!
To find the empirical formula you need the relative atomic mass of each element!
Li = 6.9
C = 12
O = 16
You can simply change the percentages into full grams
Li = 18.8g
C = 16.3g
O = 64.9
Then you use this to find the Number of moles = amount in grams / atomic mass
Li = 18.8 ÷ 6.9 = 2.7246
C = 16.3 ÷ 12 = 1.3583
O = 64.9 ÷ 16 = 4.0562
Then divide each number of moles by the smallest value:
Li = 2.7246 ÷ 1.3583 = 2.0
C = 1.3583 ÷ 1.3583 = 1
O = 4.0562 ÷ 1.3583 = 2.9 ≈ 3
So that means that there are 2 Li, 1 C, and 3 O
Empirical formula would be:
Li₂CO₃
Hope this helps!
Answer:
Explanation:
We are asked to find how many kilojoules of energy would be required to heat a block of aluminum.
We will use the following formula to calculate heat energy.
The mass (m) of the aluminum block is 225 grams and the specific heat (c) is 0.897 Joules per gram degree Celsius. The change in temperature (ΔT) is the difference between the final temperature and the initial temperature.
- ΔT = final temperature - inital temperature
The aluminum block was heated from 23.0 °C to 73.5 °C.
- ΔT= 73.5 °C - 23.0 °C = 50.5 °C
Now we know all three variables and can substitute them into the formula.
- m= 225 g
- c= 0.897 J/g° C
- ΔT= 50.5 °C
Multiply the first two numbers. The units of grams cancel.
Multiply again. This time, the units of degrees Celsius cancel.
The answer asks for the energy in kilojoules, so we must convert our answer. Remember that 1 kilojoule contains 1000 joules.
Multiply by the answer we found in Joules.
The original values of mass, temperature, and specific heat all have 3 significant figures, so our answer must have the same. For the number we found, that is the tneths place. The 9 in the hundredth place tells us to round the 1 up to a 2.
Approximately <u>10.2 kilojoules</u> of energy would be required.
Answer:
things that pollute the air
Explanation:
nuclear energy, fossil fuels, gas from cars and other transportation, and these all contribute to greenhouse gases that are harmful to the environment
hope this helped!
I'd guess A or D, but my gut says A
