How many grams of solute are needed to make 125 ml of 2.50 m nh4cl solution? round to three significant digits.

Mass = 16.7 g

Explanation:

Given data:

Volume  =  125 mL (125/1000 =0.125 L)

Molarity = 2.50 M

Mass in grams of solute = ?

Solution:

First of all we will calculate the number of moles:

Molarity = number of moles solute / volume in litter

2.50 M = Number of moles of solute/ 0.125 L

Number of moles of solute = 2.50 M × 0.125 L

Number of moles of solute = 0.313 mol

Grams of solute:

Number of moles = mass / molar mass

Mass = number of moles × molar mass

Mass =  0.313 mol × 53.5 g/mol

Mass = 16.7 g

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.

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