If a sample of salt water has a measured concentration of 21.0 ppt, how many grams of salt are there in a 2.05 kg sample of this salt water?

grams of salt = 43.05 grams

Explanation:

Salinity is the measure of the amount of dissolved salt in water. Salinity is usually expressed in part per thousand(ppt) or grams of the salt per kilogram of water. In a situation where you have 1 gram of salt and 1 kg of water , the salinity is 1 g/kg or 1 ppt.

Since 1 ppt denotes having 1 g of salt in 1000 grams of water, 21 ppt will be having 21 grams of salt in 1000 grams of water.

if 21 grams of salt → 1 000 g of water

  ? grams of salt  will be in 2050 g of water

cross multiply

grams of salt = (2050 × 21)/1000

grams of salt = 43050/1000

grams of salt = 43.05

grams of salt = 43.05 grams

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

b.

the accuracy of the data.