Question

2) A gold necklace contains 0.54 mol of gold. What is its mass in grams? 3) A helium balloon contains 0.56g of He. How many moles of He does it contain? 4) How many Na atoms in 255 g of Na3PO4? 5) Calculate the mass in grams of 6.4 x 102 NO: molecules 6) Determine the number of atoms of O in 84.0 g of CsH1005

Answer 1

Solution a) 0.54 mol of gold. molar mass of gold ie Au = 196.96 g/mol * Imol = 196.969 2 0.54mol = 0.54 x 1969 Aus= 106.35849 in 0.54 mol of gold. 3) 0.56g of He = ? moles Salimot = 48 lg = Imoles of He Aus * 0.50g = 0.56 moles of the = 0.14 moles 4) how many atoms of Na n.255g of N9₂P04 Imole of Nag Poy a 3 Not atoms & assy of Nag Poy = 1.55 moles of Nagoy

mole of Napoy a 3X NA atoms of Na. a liss moles of Na3PO4 = 341.55 KNA atome of Na a slut :- 28.10% 10% atoms 6:022 X 1023 ato mo or molecules - Imole of noz = 629/mol a 6.481021 NOg moleulles = 62 x 6,4810' - 6.022X1023 = 65.89 x 10g = 0.65899 b) mo. of atoms of om sy.og of Is Hoos. NA atoms of = Imole of es hoos = 150g ** rsnoos. * 84.0g of Eshioos o Os = I x 84.0 moles of 150" (SHoos 20.56 mole. Imole of CSMO OS > SANA atoms of o 2 . 0.56 mole of 18100g = 0.56 X SANA atoms of Ans = 16.86 x 10²3 atoms RO