Answer:
The percent by mass of water in this crystal is:
Explanation:
This exercise can be easily solved using a simple rule of three where the initial weight of the hydrated crystal (6,235 g) is taken into account as 100% of the mass, and the percentage to which the mass of 4.90 g corresponds (after getting warm). First, the values and unknown variable are established:
- 6,235 g = 100%
- 4.90 g = X
And the value of the variable X is found:
- X = (4.90 g * 100%) / 6,235 g
- X = approximately 78.6%.
The calculated value is not yet the percentage of the water, since the water after heating the glass has evaporated, therefore, the remaining percentage must be taken, which can be calculated by subtraction:
- Water percentage = Total percentage - Percentage after heating.
- <u>Water percentage = 100% - 78.6% = 21.4%</u>
168.96 g of carbon dioxide (CO₂)
Explanation:
The chemical reaction representing the combustion of acetylene:
2 C₂H₂ (g) + 5 O₂ (g)→ 4 CO₂ (g) + 2 H₂O (g)
number of moles = mass / molecular weight
number of moles of acetylene (C₂H₂) = 50 / 26 = 1.92 moles
Taking in account the stoichiometry of the chemical reaction, we devise the following reasoning:
if 2 moles of acetylene (C₂H₂) produces 4 moles of carbon dioxide (CO₂)
then 1.92 moles of acetylene (C₂H₂) produces X moles of carbon dioxide (CO₂)
X = (1.92 × 4) / 2 = 3.84 moles of carbon dioxide (CO₂)
mass = number of moles × molecular weight
mass of carbon dioxide (CO₂) = 3.84 × 44 = 168.96 g
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combustion of hydrocarbons
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Answer:
The answer is (H30+) =3,55e-8M and (OH-)=2,82e-7M
Explanation:
We use the formulas:
pH= - log(H30+) and Kwater=(H30+)x(OH-)
pH= - log(H30+) ----< (H30+)= antilog- pH=antilog- 7,45=3,55E-8M
Kwater=(H30+)x(OH-)
(OH-)=Kwater/(H30+)= 1,00e-14/3,55e-8 = 2,82e-7
a) The total pressure of the system is 1.79 atm
b) The mole fraction and partial pressure of hydrogen is 0.89 and 1.59 atm respectively
c) The mole fraction and the partial pressure of argon is 0.11 and 0.19 atm.
<h3>What is the total pressure?</h3>
We know tat we can be able to obtain the total pressure in the system by the use of the ideal gas equation. We would have from the equation;
PV = nRT
P = pressure
V = volume
n = Number of moles
R = gas constant
T = temperature
Number of moles of hydrogen = 14.2 g/2g = 7.1 moles
Number of moles of Argon = 36.7 g/40 g/mol
= 0.92 moles
Total number of moles = 7.1 moles + 0.92 moles = 8.02 moles
Then;
P = nRT/V
P = 8.02 * 0.082 * 273/100
P = 1.79 atm
Mole fraction of hydrogen = 7.1/8.02 = 0.89
Partial pressure of hydrogen = 0.89 * 1.79 atm
= 1.59 atm
Mole fraction of argon = 0.92 / 8.02
= 0.11
Partial pressure of argon = 0.11 * 1.79 atm
= 0.19 atm
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Answer: 25g/ml
Explanation:
Density = 100.0g/ 4.0mL = 25g/mL