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1 year ago

Calculate each of the following quantities:

1 answer:

5 0

The number of moles in 78.9 g of sodium perchlorate is 0.644 moles and 3.876 x 10²³ formula units are particles.

<h3>What are formula units?</h3>

Moles are converted to formula units by multiplying them by 6.02 x 1023, or Avogadro's number (Na). The moles and masses of tiny particles are estimated using this method.

Given that the mass of sodium perchlorate is 78.9 g

The molar mass of sodium perchlorate is 122.44 g/mol

Moles of sodium perchlorate will be

Moles (n) = mass ÷ molar mass

n = 78.9 g ÷ 122.44

n = 0.644 moles

If 1 mole = 6.02 x 10²³

Then, 0.644 moles = 3.876 x 10²³ particles

Thus, there are 0.644 moles of sodium perchlorate in 78.9 g.

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Balance this equation by using the correct coefficient

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2 years ago

The concentration of a NaOH solution was experimentally determined by dissolving 0.7816 grams KHP (204.2212 grams/mol) in 50.0 m

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The concentration of the standard NaOH solution is 0.094 moles/L.

Explanation:

In the titration, the equivalence point is defined as the point where the moles of NaOH (the titrant) and KHP (the analyte) are equal:

moles of NaOH = moles of KHP

$[NaOH]xV_{NaOH} = moles of KHP$

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2 years ago

a substance has a vapor pressure of 0.2020 atm at 261.5 k. if its heat of vaporization is 20.94 kj/mol, calculate its vapor pres

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The vapor pressure at the new temperature can be obtained as 0.074 atm.

<h3>What is the vapor pressure?</h3>

The term vapor pressure has to do with the pressure that accumulates owing to the fact that some of the liquid is leaving the solution and gets to the top of the container.

Now we have the formula;

ln(P2/P1) = -ΔHvap/R(1/T2 - 1/T1)

P2 = final pressure

P1 = initial pressure

ΔHvap = Enthalpy of vaporization

T2 = final temperature

T1 = initial temperature

ln(P2/0.2020) = -20.94 * 10^3/8.314(1/240.9 - 1/261.5)

ln(P2/0.2020) = -2518.6(0.0042 - 0.0038)

ln(P2/0.2020) = -1.00744

Taking the exponential of both sides;

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9 months ago