ِAnswer:
1- The molarity of HCOOH = 9.515 M.
2- The mole fraction of HCOOH = 0.18.
Explanation:
<em>1- The molarity of HCOOH:</em>
- We can calculate the molarity of HCOOH using the relation:
M = (10pd)/molar mass.
p is the percent by mass of HCOOH = 35.9 %.
d is the specific gravity of HCOOH = 1.22 g/cm³.
Molar mass of HCOOH = 46.03 g/mol.
∴ M = (10pd)/molar mass = (10)(35.9 %)(1.22 gcm³) / (46.03 g/mol) = 9.515 M.
<em>2- The mole fraction of HCOOH:</em>
- We can suppose that we have a 100 g solution, that contains 35.9 g of HCOOH and 64.1 g of water.
<em>The mole fraction of HCOOH = (no. of moles of HCOOH) / (no. of moles of HCOOH + no, of moles of water).</em>
no. of moles of HCOOH = mass / molar mass = (35.9 g)/(46.03 g/mol) = 0.78 mol.
no. of moles of water = mass / molar mass = (64.1 g)/(18.0 g/mol) = 3.56 mol.
- The mole fraction of HCOOH = (no. of moles of HCOOH) / (no. of moles of HCOOH + no, of moles of water) = (0.78 mol) / (0.78 mol + 3.56 mol) = 0.18.
To determine the number of moles of HCl from 2 moles of H2, we take stoichiometry to solve this problem. The balanced equation is 2HCl= H2+Cl2 Using stoichiometry, the expression becomes 2 mole H2*(2 molHCl/1 mole H2). The answer is 4 moles.
Answer: Incomplete/half answer
Explanation:
grams of molar mass of the
substance substance in grams
––––––––––– = –––––––––––––––
moles of the
substance one mol
use this formula to asnwer the question
The molar mass of O2 is 32g/mol. So the mol amount of these O2 is 56/32=2 mol. STP stands for the standard temperature and pressure which means the temperature is 0 ℃ and pressure is 100 kPa. And the molar volume of gas is 22.7 L/mol under STP. So the answer is 22.7*2=45.4 L
When atoms and molecules speed up or slow down, that is a physical change. When they change state from liquid to solid or from gas to liquid, that is a physical change. ... The ions or molecules can still come back together to form the original substance
