How many half lives would pass if a mass of copper-66 decayed for 51 minutes? The half life of Cu-66 is 5.10 minutes.
1 answer:
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Answer:
1 - Salts required that can be compared directly, using Ksp values, to estimate solubilities for copper (II) sulfide are - (Option b) ,
(Option c) and
(Option d)
2 - Salts that can be compared directly, using Ksp values, to estimate solubilities for zinc hydroxide are - (Option a)
Explanation:
values can be used to compare the solubility of salts that produce ions in a 1:1 ratio.
{copper (II)sulfide} dissociates with ions in ratio 1:1 .
Because the salts ,
and
have a 1:1 ion ratio, the solubilities of options b, c, and d can be compared to salt 1.
Values can be used to compare the solubility of salts that produce ions in a 1:2 or 2:1 ratio.
2. dissociates into ions in ratio 1:2 .
Because the ions in the salt are in a 1:2 ratio, the solubility of salt 2 can be compared to that of salt 'a'.
Hence , Salt 1 is matched with options b , c , d.
Salt 2 is matched with option a.
N2O4(l) + 2 N2H4(l) → 3 N2(g) + 4 H2O(g)
1) to calculate the limiting reactant you need to pass grams to moles.
<span> moles is calculated by dividing mass by molar mass
</span>
mass of N2O4: 50.0 g
molar mass of <span>N2O4 = 92.02 g/mol
</span><span>molar mass of N2H4 = 32.05 g/mol.
</span>mass of N2H4:45.0 g
moles N2O4=50.0/92.02 g/mol= 0,54 mol of N2O4
moles N2H4= 45/32.05 g/mol= 1,40 mol of <span><span>N2H4
</span> 2)</span>
By looking at the balanced equation, you can see that 1 mol of N2O4 needs 2 moles of N2H4 to fully react . So to react 0,54 moles of N2O4, you need 2x0,54 moles of <span>N2H4 moles
</span><span>N2H4 needed = 1,08 moles.
You have more that 1,08 moles </span><span>N2H4, so this means the limiting reagent is not N2H4, it's </span>N2O4. The molecule that has molecules that are left is never the limiting reactant.
3) 1 mol of N2O4 reacting, will produce 3 mol of N2 (look at the equation)
There are 0,54 mol of N2O4 available to react, so how many moles will produce of N2?
1 mol N2O4------------3 mol of N2
0,54 mol N2O4--------x
x=1,62 mol of N2
4) the only thing left to do is convert the moles obtained, to grams.
We use the same formula as before, moles equal to mass divided by molar mass.
(molar mass of N2= 28)
1,62 mol of N2= mass/ 28
mass of N2= 45,36 grams
1) to calculate the limiting reactant you need to pass grams to moles.
<span> moles is calculated by dividing mass by molar mass
</span>
mass of N2O4: 50.0 g
molar mass of <span>N2O4 = 92.02 g/mol
</span><span>molar mass of N2H4 = 32.05 g/mol.
</span>mass of N2H4:45.0 g
moles N2O4=50.0/92.02 g/mol= 0,54 mol of N2O4
moles N2H4= 45/32.05 g/mol= 1,40 mol of <span><span>N2H4
</span> 2)</span>
By looking at the balanced equation, you can see that 1 mol of N2O4 needs 2 moles of N2H4 to fully react . So to react 0,54 moles of N2O4, you need 2x0,54 moles of <span>N2H4 moles
</span><span>N2H4 needed = 1,08 moles.
You have more that 1,08 moles </span><span>N2H4, so this means the limiting reagent is not N2H4, it's </span>N2O4. The molecule that has molecules that are left is never the limiting reactant.
3) 1 mol of N2O4 reacting, will produce 3 mol of N2 (look at the equation)
There are 0,54 mol of N2O4 available to react, so how many moles will produce of N2?
1 mol N2O4------------3 mol of N2
0,54 mol N2O4--------x
x=1,62 mol of N2
4) the only thing left to do is convert the moles obtained, to grams.
We use the same formula as before, moles equal to mass divided by molar mass.
1,62 mol of N2= mass/ 28
mass of N2= 45,36 grams