How many grams of caf2 would be needed to produce 1.23 moles of f2?

We see from the chemical formula itself that there is 1 mole of F2 for every 1 mole of CaF2, hence the number of moles of CaF2 is also:

moles CaF2 = 1.23 moles

The molar mass of CaF2 is 78.07 g/mol, so the mass is:

mass CaF2 = 78.07 g / mol * 1.23 mol

mass CaF2 = 96.03 grams

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.