150.0 g of NaCl (mm: 58.5 g/mol) is dissolved in 250.0 ml of water calculate the molarity

10.26 M

Explanation:

The definition of molarity is moles per liter. Since we are given the mass, we first convert it into moles. Then, we divide by the amount of liters. A common way to solve the problem is through dimensional analysis. In it, you multiply all the numbers on top and divide by the numbers in the bottom.

150g     |        mol        |                          |    1000 mL

   = 10.26 M

            |     58.5 g       |        250 mL     |       1 L

This is the same as 150 * 1000 / (58.5 * 250) = 10.26M.

You can double check that you get the correct units by crossing out the same units on top and bottom. At the end, you should be left with a mol on top and L in the bottom. mol/L = molarity (M).

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.