Answer:
[HClO₄] = 11.7M
Explanation:
First of all we need to know, that a weight percent represents, the mass of solute in 100 g of solution.
Let's convert the mass to moles → 70.5 g . 1mol/100.45 g = 0.702 moles
Now we can apply the density to calculate the volume.
Density always refers to solution → Solution density = Solution mass / Solution volume
1.67 g/mL = 100 g / Solution volume
Solution volume = 100 g / 1.67 g/mL → 59.8 mL
To determine molarity (mol/L) we must convert the mL to L
59.8 mL . 1L/1000mL = 0.0598 L
Molarity → Moles of solute in 1L of solution → 0.702 mol / 0.0598 L = 11.7M
Answer is: the mass of a block of magnesium is 177.75 grams.
m(Fe) = 826 g.
d(Fe) = 7.9 g/cm³.
1) Calculate volume of iron and magnesium:
d(Fe) = m(Fe) ÷ V(Fe).
V(Fe) = m(Fe) ÷ d(Fe).
V(Fe) = 826 g ÷ 7.9 g/cm³.
V(Fe) = V(Mg) = 104.56 cm³.
2) Calculate mass of magnesium:
m(Mg) = V(Mg) · d(Mg).
m(Mg) = 104.56 g/cm³ · 1.7 g/cm³.
m(Mg) = 177.75 g.
the balanced chemical equation for decomposition of HgO is as follows
2HgO --> 2Hg + O₂
stoichiometry of HgO to O₂ is 2:1
number of HgO moles heated are - 3.00 g / 216.59 g/mol = 0.0139 mol
according to stoichiometry of reaction -
number of O₂ moles formed = 0.0139 mol/ 2 = 0.00695 mol
mass of O₂ to be formed - 0.00695 mol x 32.00 g/mol = 0.2224 g
but the actual yield = 0.195 g
percent yield = actual yield / theoretical yield x 100 %
percent yield = 0.195 g / 0.2224 g x 100 % = 87.7 %
answer is 87.7 %
Answer:
145 hours
Explanation:
Since one hour of riding a bicycle takes up 505 kcal of energy. It is also stated that one gram of body fat is equal to 7.70 kcal. Also, it is given that 1 pound of body fat is equal to 454 g.
Hence;
1 Ib= 454 g
21 Ib= 21 × 454/1 = 9534 g
But
1g of body fat = 7.70kcal
9534 g of body fat = 9534 × 7.70 kcal/1 = 73411.8 kcal
If 505 kcal is lost in 1 hour
73411.8 kcal is lost in 73411.8 kcal × 1hour/505k cal = 145 hours
<h3>
Answer:</h3>
1 x 10^13 stadiums
<h3>
Explanation:</h3>
We are given that;
1 stadium holds = 1 × 10^5 people
Number of iron atoms is 1 × 10^18 atoms
Assuming the stadium would carry an equivalent number of atoms as people.
Then, 1 stadium will carry 1 × 10^5 atoms
Therefore,
To calculate the number of stadiums that can hold 1 × 10^18 atoms we divide the total number of atoms by the number of atoms per stadium.
Number of stadiums = Total number of atoms ÷ Number of atoms per stadium
= 1 × 10^18 atoms ÷ 1 × 10^5 atoms/stadium
= 1 × 10^13 Stadiums
Thus, 1 × 10^18 atoms would occupy 1 × 10^13 stadiums
