How many molecules of sucrose (c12h22o11, molar mass = 342.30 g/mol) are contained in
14.3 ml of 0.140 m sucrose solution?

molecules

Explanation :  

Molarity is defined as the number of moles of solute dissolved per liter of the solution.

where,

n = moles of solute = ?

= volume of solution in liter = 0.0143L

Now put all the given values in the formula of molarity, we get

Therefore, the number of moles is 0.002.

According to Avogadro's law,

1 mole of contains molecules of sucrose.

Thus 0.002 moles of contain= molecules of sucrose.

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

the answer would be a