Nick needs 3.5 moles of sodium fluoride (NaF) for a solution he is mixing in the lab. How many grams of NaF does Nick need to measure out?

147 g

Explanation:

The number of moles of a substance is the ratio of the mass of the substance and the molar mass of that substance. Mathematically,

  mole = mass of substance/molar mass

In this case, Nick needs 3.5 moles of NaF, the molar mass of NaF is calculated as:

  23 + 19 = 42 g/mol (Note: Na = 23, F = 19)

Hence,

mass of 3.5 mole NaF = mole x molar mass

                              = 3.5 x 42 = 147 g.

Hence, Nick would need to measure out 147 g NaF using a suitable weighing balance.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.