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3 years ago

What is the molecular formula if the percent composition is 58.8C 9.8H 31.4O

1 answer:

4 0

You only can calculate the empirical formula with that information. I can not guarantee the empirical formula is going to be the same than the molecular formula. To be able to calculate the molecular formula you need the molecular mass or other information.

58.8/12= C = 4.9 => 4.9/1.96 = 2.5 => 2.5*2= 5
9.8/1= H = 9.8 => 9.8/1.96 = 5 => 5* 2= 10
31.4/16=O = 1.96 =>1.96/1.96 = 1 => 1*2 =2

empirical formula C5H10O2

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Trimix 10/50 is a gas mixture that contians 10% oxygen and 50% helium, and the rest is nitrogen. If a tank of trimix 10/50 has a

Nataly_w [17]

Answer: 1.61 x 10⁴ kPa

Dalton's law states that the sum of the partial pressures of each gas equals the total pressure of the gas mixture. According to this law,

Pi = xi P

where Pi is the partial pressure of the gas i, xi is the mole fraction of the gas i in the gas mixture and P is the total pressure.

The mole fraction is defined as the quotient between the moles of solute (ni) and the total moles of the mixture (nt), which is calculated by adding the moles of all its components:

xi = $\frac{n_{i} }{n_{t} }$

In the Trimix 10/50 mix you have 10% oxygen, 50% helium and 40% nitrogen.

To calculate the total number of moles of the mixture and thus determine the molar fraction of helium, we consider 100 g and calculate the number of moles that represent 10 g of O₂ (n₁), 50 g of He (n₂) and 40 g of N₂ (n₃):

n₁ = 10 g x $\frac{1 mol}{31.998 g}$ = 0.313 mol

n₂ = 50 g x $\frac{1 mol}{8.005 g}$ = 6.246 mol

n₃ = 40 g x $\frac{1 mol}{28.013 g}$ = 1.428 mol

Then the total number of moles (nt) will be:

nt = n₁ + n₂ + n₃ = 0.313 mol + 6.246 mol +1.428 mol

nt = 7,987 mol

Then, the mole fraction of helium (x₂) in the mixture will be,

x₂ = $\frac{6.246 mol}{7.987 mol}$ = 0.78

and the partial pressure of helium in the mixture, according to Dalton's law, will be:

P₂ = x₂ P = 0.78 x 2.07 x 10⁴ kPa

P₂= 1.61 x 10⁴ kPa

So, the partial pressure of helium if a tank of trimix 10/50 has a total pressure of 2.07 x 104 kPa is 1.61 x 10⁴ kPa

5 0

3 years ago

Given the balanced equation representing a

zhannawk [14.2K]

Answer: it would be a 1 to 1 ratio

Explanation: originally it would be 2 to 2 but you have to reduce

4 0

2 years ago

If the K a Ka of a monoprotic weak acid is 7.3 × 10 − 6 , 7.3×10−6, what is the pH pH of a 0.40 M 0.40 M solution of this acid?

olga_2 [115]

Answer:

pH =3.8

Explanation:

Lets call the monoprotic weak acid HA, the dissociation equilibria in water will be:

HA + H₂O ⇄ H₃O⁺ + A⁻ with Ka = [ H₃O⁺] x [A⁻]/ [HA]

The pH is the negative log of the H₃O⁺ concentration, we know the equilibrium constant, Ka and the original acid concentration. So we will need to find the [H₃O⁺] to solve this question.

In order to do that lets set up the ICE table helper which accounts for the species at equilibrium:

HA H₃O⁺ A⁻

Initial, M 0.40 0 0

Change , M -x +x +x

Equilibrium, M 0.40 - x x x

Lets express these concentrations in terms of the equilibrium constant:

Ka = x² / (0.40 - x )

Now the equilibrium constant is so small ( very little dissociation of HA ) that is safe to approximate 0.40 - x to 0.40,

7.3 x 10⁻⁶ = x² / 0.40 ⇒ x = √( 7.3 x 10⁻⁶ x 0.40 ) = 1.71 x 10⁻³

[H₃O⁺] = 1.71 x 10⁻³

Indeed 1.71 x 10⁻³ is small compared to 0.40 (0.4 %). To be a good approximation our value should be less or equal to 5 %.

pH = - log ( 1.71 x 10⁻³ ) = 3.8

Note: when the aprroximation is greater than 5 % we will need to solve the resulting quadratic equation.

4 0

3 years ago

Which list of elements consists of a metal, a metalloid, and a nonmetal?

Irina18 [472]

Answer:

Sn, Si, C

Explanation:

8 0

3 years ago

Which solution has the lowest freezing point?

Leokris [45]

Correct Answer: Option 3 i.e. 30 g of KI dissolved in 100 g of water.

Reason:
Depression in freezing point is a colligative property and it is directly proportional to molality of solution.

Molality of solution is mathematically expressed as,
Molality = $\frac{\text{Number of moles}}{\text{Weight of solvent (Kg)}}$ 

In case of option 1 and 2, molality of solution is 0.602 m. For option 3, molality of solution is 1.807 m, while in case of option 4, molality of solution is 1.205 m.

Thus, second solution (option 2) has highest concentration (in terms of molality). Hence, it will have lowest freezing point

3 0

4 years ago

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