To convert grams to moles, we need the molar mass of the element or compound. remember you can determine the molar mass of a molecule by adding the atomic mass of each atom from the periodic table.
molar mass of Na= 23.0 g/ mol
130 g (1 mol Na/ 23.0 grams)= 5.65 moles or 6 moles.
Answer:
9.606 grams of citric acid are present in 125 mL of a 0.400 M citric acid solution.
Explanation:
Molarity : It is defined as the number of moles of solute present in one liter of solution. Mathematically written as:

Moles of citric acid = n
Volume of the citric acid solution = 125 mL =125 × 0.001 L= 0.125 L
(1 mL = 0.001L)
Molarity of the citric acid solution = 0.400 M

n = 0.400 M × 0.125 L = 0.05 moles
Mass of 0.05 moles of citric acid :

9.606 grams of citric acid are present in 125 mL of a 0.400 M citric acid solution.
I got on here because I don't understand the question but I did my best to answer because I noticed you asked 3 days ago. IF I'm right the answer is D. My diagram shows
A at -50 °C
B at 0 °C
C at 50 °C
D at 100 °C (gas to liquid or liquid to gas)
And E at 150 °C
So I hope I'm right because I'm answering the same question.
Two isotopes of the same element will have the same ATOMIC NUMBER but a different MASS NUMBER.
Answer:
b. Cu(OH)2
Explanation:
As it is having Hydroxil ions(OH).