Question

Use the following molecular weights:

C = 12.0107 H = 1.00794 O = 15.9994 N = 14.00674 Fe = 55.845 S = 32.06 Co = 58.93 Na = 22.9898

Question 1: Your molecular weights are given above, where would you find these if they were not given? 1 mark

Question 2: How many moles are in 2.0 g Sodium? 2 marks

Question 3: How many grams in 2.3 mol SO4? 2 marks

Question 4: When working in a lab over the holidays you find a vial of blue powder. The label is unintelligible, and the only thing can read is: Substance: Co(CX)6 Moles: 0.0189mol You weigh the sample: Grams: 4.29g What is the compound? (Hint: what is X?) 9 marks 4

Question 5: How many atoms are in 62g of NH3? 3 marks

Answer 1

(1) We con get malecular weight os all clements from periodic table. 2 Male moss 2.0 gm malar mas 222.9898 ginal = 0.087 mal نر Moss mal X Malor mon 2.3 X 96.057 mala moss os 220.93 gm 32. 06 4 X 15.9994 sou 96.057 glmal malor mass 4.29 goo U moss male 0.0189 mol 226.98 glmal mala moss Colex), Mco + 6XMc + 6xMy 226.98 1' 58.93 + 6 X 12-010 + 6 Xmx 6 x my 226.98 = 58.93 72.06 6Xм, 95.9941 MX 15.999 gm Malecular weight of x malicular weight of 0 X = Oacy gen

S 62 gm man Maler mars = 17 glmal 11 Mal = mass 62 = 3.647 mal Malar men It ginal One mal contain INA ( 6.0223 x 1023) atom Atoms in 3.647 mal 6,0223 x 1023 x 3.647 ay N43 ذر 21.96 X 10 23 atoms