Answer:
Explanation:
Here, we want to calculate the number of formula units in the given molecule
We start by getting the number of moles
To get the number of moles, we have to divide the mass given by the molar mass
The molar mass is the mass per mole
The molar mass of calcium bromide is 200 g/mol
Thus, we have the number of moles as follows:
The number of formula units in a mole is:
The number of formula units in 0.2075 mole will be:
The volume of hydrogen gas that evolved is calculated as follows
by use of ideal gas equation
that is PV = nRT
P=745 mm hg
V= ?
R(gas constant)= 62.36 L.mm hg/mol.k
T= 20 + 273 = 293 k
n=number of moles which is calculated as follows
find the moles of Na used
= 0.52/23=0.023 moles
write the reacting equation
2Na +2H2O =2NaOH +H2
by use of reacting ratio between Na : H2 which is 2:1 therefore the mole of H2 = 0.023/2 =0.0115 moles
by making the volume the subject of the formula
v=nRT/P
V= (0.0115 x 62.36 x 293) / 745 = 0.283 L
240 g NaOH
<em>Step 1</em>. Calculate the moles of NaOH
Moles of NaOH = 0.750 L solution × (8 mol NaOH/1 L solution) = 6 mol NaOH
Step 2. Calculate the mass of NaOH
Mass of NaOH = 6 mol NaOH × (40 g NaOH/1 mol NaOH) = 240 g NaOH
