360 mg / 1000 => 0.36 g
molar mass => 180 /mol
number of moles:
mass of solute / molar mass
0.36 / 180 => 0.002 moles
Volume solution = 200 mL / 1000 => 0.2 L
M = n / V
M = 0.002 / 0.2
M = 0.01 mol/L
hope this helps!
Answer:
The first one.

Explanation:
When comparing two fractions with variables like this, it's important to get to the same denominator in order to compare apples with apples and then be able to do not only comparisons but also perform additions/subtractions.
Question is which denominator to use and how to reach it.
In this case, the question and the answer choices do the work for you. The question asks which one is the LEAST common denominator, and the answers show denominators x² and 4x². The smallest of these is x², however, we can't simplify the first fraction to get to the x² denominator, so we'll go for the 4x².
So, the first fraction has already the correct denominator (4x²), we just have to transform the second one.
We multiply it by 1, expressed in a different way. Since we're multiplying by one, we're not affecting the value, just the way it looks.
Let's do it!, to get the denominator to go from x² to 4x², we need to multiply it by 4... so we'll multiply by 4/4 (which is 1, neutral for the multiplication).

And now you have both fractions on the same denominator, without having changed their value, just their looks
<span>Determine the root-mean-square sped of CO2 molecules that have an average Kinetic Energy of 4.21x10^-21 J per molecule. Write your answer to 3 sig figs.
</span><span>
E = 1/2 m v^2
If you substitute into this formula, you will get out the root-mean-square speed.
If energy is Joules, the mass should be in kg, and the speed will be in m/s.
1 mol of CO2 is 44.0 g, or 4.40 x 10^1 g or 4.40 x 10^-2 kg.
If you divide this by Avagadro's constant, you will get the average mass of a CO2 molecule.
4.40 x 10^-2 kg / 6.02 x 10^23 = 7.31 x 10^-26 kg
So, if E = 1/2 mv^2
</span>v^2 = 2E/m = 2 (4.21x10^-21 J)/7.31 x 10^-26 kg = 115184.68
Take the square root of that, and you get the answer 339 m/s.
Hi!
The correct option would be 3.85x10^(24)
To find the number of atoms in 250g of potassium, we need to first calculate the number of atoms in
1 mole of Potassium = 39g which contains 6.022x10^(23) atoms of K
<em>(Avogadro's constant value for the amount of molecules/atoms in one mole of any substance)</em>
<em>Solution</em>
So as 39g of Potassium contains 6.022x10^(23) K atoms
1g of Potassium would contain 6.022x10^(23) / 39 = 1.544 x10^(22) atoms
So 250g of Potassium would contain 1.544x10^(22) x 250 = 3.86x10^(24) atoms