Question

URGENT!!!
A sample of silver chromate has a mass of 25.8 grams

a) How many formula units of silver chromate in the given mass? (5 marks)

b) How many cations are present in the sample? (3 marks)

c) How many anions are present in the sample? (2 marks)

d) What is the mass in grams of one formula unit of silver chromate? (4 marks)

Answer 1

Explanation:

A sample of silver chromate has a mass of 25.8 grams

Below are the answers of given questions -

a) The formula of silver chromate is $Ag_{2}CrO_{4}$

b) First we determine the molar mass of sodium sulfate $Ag_{2}CrO_{4}$  

  Molar mass of $Ag_{2}CrO_{4}$  is 331.74 g/mol  

  Moles of  $Ag_{2}CrO_{4}$ = 0.078 mol

  Hence, 6.92 × 10²² $Ag^{+}$ ions cations are present in the sample.

c) We calculate the number of  $CrO^{2-}_{4}$ ions by using the ratios from the          chemical formula as conversion factors

4.7 × 10²² $Ag_{2}CrO_{4}$  molecules × $\frac{1CrO^{2-}_{4} }{1 molecule Ag_{2}CrO_{4} }$   = 4.7 × 10²² $CrO^{2-}_{4}$ ions.

Hence, 6.92 × 10²² $CrO^{2-}_{4}$ ions

d) We calculate the mass in grams of one formula unit of  $Ag_{2} CrO_{4}$ by using the inverse of Avogadro's number as a conversion factor.

$\frac{331.74Ag_{2}CrO_{4} }{1 mol}$ ×$\frac{1 mol}{6.022}$ ×10²³ formula units = 5.51 ×  10²²g $Ag_{2} CrO_{4}$/ formula unit.

Answer 2

Answer:

A sample of silver chromate has a mass of 25.8 grams

Below are the answers of given questions -

a) The formula of silver chromate is

b) First we determine the molar mass of sodium sulfate  

 Molar mass of   is 331.74 g/mol  

 Moles of   = 0.078 mol

 Hence, 6.92 × 10²²  ions cations are present in the sample.

c) We calculate the number of   ions by using the ratios from the          chemical formula as conversion factors

4.7 × 10²²   molecules ×    = 4.7 × 10²²  ions.

Hence, 6.92 × 10²²  ions

d) We calculate the mass in grams of one formula unit of   by using the inverse of Avogadro's number as a conversion factor.

× ×10²³ formula units = 5.51 ×  10²²g / formula unit.