What is the name of the compound H₃S₅?

The vapor pressure of water at 25.0°C is 23.8 torr. Determine the mass of glucose (molar mass = 180 g/mol) needed to add to 500.

mrs_skeptik [129]

According to Raoult's law the relative lowering of vapour pressure of a solution made by dissolving non volatile solute is equal to the mole fraction of the non volatile solute dissolved.

the relative lowering of vapour pressure is the ratio of lowering of vapour pressure and vapour pressure of pure solvent

$\frac{p^{0-}p}{p^{0}}=x_{B}$

Where

xB = mole fraction of solute=?

$p^{0}=23.8torr$

p = 22.8 torr

$x_{B}=\frac{23.8-22.8}{23.8}=0.042$

mole fraction is ratio of moles of solute and total moles of solute and solvent

moles of solvent = mass / molar mass = 500 /18 = 27.78 moles

putting the values

$molefraction=\frac{molessolute}{molesolute+molessolvent}$

$0.042=\frac{molessolute}{27.78+molessolute}$

$1.167+0.042(molesolute)=molessolute$

$molessolute=1.218$

mass of glucose = moles X molar mass = 1.218 X 180 = 219.24 grams

3 0

3 years ago

Isotopes of an element have the same number of ________ and different numbers of ________. neutrons... protons protons... neutro

Ivahew [28]

Protons . . . neutrons

8 0

3 years ago

A 0. 462 g sample of a monoprotic acid is dissolved in water and titrated with 0. 180 m koh. what is the molar mass of the acid

Len [333]

The molar mass of the acid if 28. 5 ml of the koh solution is required to neutralize the sample is 90.23g/mol.

<h3>For the calculation of molarity of solution</h3>

Molarity = (moles of solute/volume of solution) × 1000

Given,

Molarity of KOH solution = 0.180 M

Volume of solution = 28.5 mL

0.180 = (moles of KOH/ 28.5) × 1000

Moles = (0.18× 28.5)/1000

= 0.00513 mol

<h3>Chemical equation for the reaction</h3>

HA + KOH ------- KA + H2O

1 moles of KOH reacts with 1 moles of HA.

So, 0.00513 moles of KOH react with 0.00513 moles of HA.

<h3>To calculate the molar mass for given number of moles</h3>

Number of moles= given mass/ Molar mass

Given,

Mass of HA = 0.462 g

Moles of HA = 0.00512 mol

0.00512 = 0.462/ Molar mass

Molar mass = 90.23 g/ mol.

Thus the molar mass of HA required to neutralize the 28.5 mL of KOH is 90.23g/mol.

learn more about molar mass or moles:

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3 0

1 year ago

The end point of a titration is defined as the volume of titrant added, while the equivalence point is the volume required for c

saw5 [17]

Answer:

...BY CHOOSING A PROPER INDICATOR, SCIENTISTS CAN MINIMIZE THE DIFFERENCE IN THESE TWO NUMBERS,...

Explanation:

A chemical indicator is an agent or substance which gives a visible sign especially a color change when introduced to a solution of base indicating the threshold of the concentration of acid used in the titration procedure. These indicators include methyl orange, methyl red, phenolpthalein. They give a color change when the concentration of an acid as reached a critical limit in order for the reaction to be stopped. These indicators are involved in acid-base titrations, oxidation- reduction reactions and so on. More accurate results of the volume of the required acid or base is obtained by the introduction of these indicators.

8 0

3 years ago

How do the first ionization energies of main group elements vary across a period and down a group?

meriva

They increase across each period, decrease down a group. As you go across a period the number of protons and increases. The positive nucleus then has a stronger attractive force on the electrons so it takes a larger amount of energy to remove an electron. As you go down a group the atoms are larger so the attractive force is weaker and it takes less energy to remove an electron.

8 0

3 years ago