SHOW CALCULATIONS FOR THE FOLLOWING 1.) How many moles is 48.2g of Si? b. How ma
ID: 1006223 • Letter: S
Question
SHOW CALCULATIONS FOR THE FOLLOWING
1.) How many moles is 48.2g of Si?
b. How many atoms
2.) A compund of carbon and hydrogen and oxygen ( ethylene glycole-antifreeze) is determined to be 38.7% C , 51.6% O, and 9.7%H . Calculate the molecular formula if the molar mass is 62.1g/mol. Show calculations.
3.)How many grams of Fe can be recovered from 35.0g of Fe2O3? Show calculations
4.) How many atoms of O in 4.80g of Ca(ClO3)2? Show calculations.
5.)How many liters(at STP) are 5.39 * 10^25 molecules of nitrogen monoxide?
6.) Describe the preparation of 500. ml of a .150M LiNO3 solution. Show calculation.
7.)a. Write a complete balanced conventional (Molecular ) equation . b.) Wite the complete ionic equation. c). Write the net ionic equation and include all the charges for the following.
i.) A solution of Barium nitrate is added to a solution of sodium hydroxide.
ii) A solution of ammonium hydroxide is mixed with a solution of aluminum nitrate.
iii)A solution of strontium hydroxide is added to a solution of hydrochloric acid.
iv) A solution of copper(II) chloride is mixed with a solution of sodium carbonate.
Explanation / Answer
1. no of moles of Si = W/G.A.Wt
= 48.2/28 = 1.72 moles
no of atoms = no of moles * 6.023*1023
= 1.72 *6.023*1023
= 1.036*1024 atoms
2.
Element % At.Wt Relative number simple ratio
C 38.7 12 38.7/12 = 3.225 3.225/3.225 = 1
H 9.7 1 9.7/1 = 9.7 9.7/3.225 = 3
O 51.6 16 51.6/16 = 3.225 3.225/3.225 = 1
Empirical formula = CH3O = 31
empirical formula mass = 12+3+16
molecular formula = (empirical formula)n
n = molar mass/empirical formula mass
= 62.1/31 = 2
molecular formula = (CH3O)2
C2H6O2 >>>> answer
3.)How many grams of Fe can be recovered from 35.0g of Fe2O3?
no of moles of Fe2O3 = 35/160 = 0.218 moles
Fe2o3- ------> 2Fe
0.218 moles 2*0.218 = 0.436 moles
mass of Fe = no of moles * atomic mass of Fe
= 0.436*56 = 24.416g
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