1) what type of solution (saturated or unsaturated ) is present for Pb(NO3)2 if at approximately 25 degrees c ,65 grams of the substance are present in the 100 grams of H2O

2)40 grams of KCl are dissolve in 100 grams of H2O at 10 degrees c how many grams will not dissolve

3)how many grams of H2O are needed to dissolve 50 grams of KClO3 at 70 degrees C

4)how many grams of K2Cr2O7 will dissolve in 75 grams of H2O at 90 degrees C

5) 59 grams of CaCl2 are dissolve in 100 grams of water at approximately 25 degrees c how many more grams of CaCl2 must be added to saturate the solution

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2