Petunia needs 66.48 grams of potassium hydroxide (KOH) to run a reaction in class. How many moles of potassium hydroxide does sh
1 answer:
Answer:
She needs 1.19 moles of potassium hydroxide.
Explanation:
Being the molar mass of the elements:
- K= 39 g/mole
- O= 16 g/mole
- H= 1 g/mole
then the molar mass of potassium hydroxide is:
KOH= 39 g/mole + 16 g/mole + 1 g/mole= 56 g/mole
Being the mass of one mole of a substance, which can be an element or a compound, you can apply the following rule of three: if 56 g of KOH are present in 1 mole, 66.48 g of KOH in how many moles of the compound are they?
moles of KOH= 1.19
<u><em> She needs 1.19 moles of potassium hydroxide.</em></u>
You might be interested in
Answer:
a) 0,2% w/v
b) r=500
c) 0,0182 M
d) 0,0145 m
e) 0,0137 equivalents
Explanation:
a) % w/v means mass of solute in grams per 100 mililiter of solution. Thus:
%w/v= ×100 = 0,2%w/v
b) Ratio strength is a way to express concentration. For w/v is in 1g of solute <em>r</em> mililiters of solution have. Thus, r = 500 because we have in the first 1 g of CaCl₂ in 500 mL of solution.
c) Molarity is moles of solute per liter of solution, thus:
1,000 g of CaCl₂ × = 9,09×10⁻³ moles of CaCl₂
500 mL of solution × = 0,500 L of solution
M = = 0,0182 M
d) Molality is moles of solute per kg of solution.
Specific gravity is the ratio between density of the solution and density of a reference substance (Usually water). With a specific gravity of 0,8:
kg of solution = 0,500 L of solution × =<em> </em><em>0,625 kg of solution</em>
m = = 0,0145 m
e) In a salt, equivalents are the number of moles ables to replace one mole of charge. In CaCl₂ is ¹/₂ because with ¹/₂ moles of CaCl₂ it is possible to replace 1 mole of charges. Thus, in 1,5 L there are:
1,5 L × ×
= 0,0137 equivalents
I hope it helps!