Chemistry High School

Of a non-volatile solute is dissolved in 365.0 g of water. the solute does not react with water nor dissociate in solution. assume that the resulting solution displays ideal raoult's law behaviour. at 70°c the vapour pressure of the solution is 231.16 torr. the vapour pressure of pure water at 70°c is 233.70 torr. calculate the molar mass of the solute (g/mol).

Answers

Answer 1
by using this formula of vapor pressure:
Pv(solu)= n Pv(water) 
when we have Pv(solu)=231.16 torr & Pv(water)= 233.7 torr
from this formula, we can get n (mole fraction of water) by substitution:
231.16 = n * 233.7
∴ n(mole fraction of water) = 0.99
so mole fraction of solution = 1 - 0.99 = 0.01
when no.of moles of water = mass weight / molar weight
                                             = 365g / 18g/mol = 20 moles
Total moles in solution =  moles of water / mole fraction of water
                                      = 20 / 0.99 =20.2
no. of moles of the solution= total moles in solution- moles of water
                                              = 20.2 - 20 = 0.2 moles
when we assumed the mass weight of the solution = 16 g (missing in your question should be given)
∴ molar mass = mass weight of solute / no. of moles of solute
                        = 16 g / 0.2 mol = 80 g/mol
 

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Answers

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Hope this helps! :)

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Answers

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B2H6,  HCl,  NH3, NO2  and  S2F4  since  their  bond  involve  between  two  non  metals

Answers:

B2H6

HCl

Sn(SO4)

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I did the quiz, it's correct.

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Answers

They use a pH meter. The scale is called pH scale, any value below 7 is acidic

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Answers

I believe the answer is C, hydrogen bonds. A water molecule consist of two hydrogen atoms bonded to an oxygen atom, and a bent overall structure. Water molecules can only form hydrogen bonds between the partially positively charged hydrogen atoms in water molecules and a partially negatively charged atom in another molecules say oxygen in another water molecule.

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b. carbonsc. silicons
d. graphites _________ 6. at room temperature, most metals are ______.
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b. solids
c. radioactive
d. gases _________ 7. an allotrope of carbon that is hard and is often used in jewelry is ______.
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b. diamond
c. quartz
d. graphite _________ 8. metals can be used as wire because they are ______.
a. ductile
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c. shiny
d. alloys _________ 9. the ______ often occur in nature as uncombined elements.
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Answers

1. An allotrope of carbon that is soft and can be used as a lubricant is d. graphite.
Graphite is the most stable allotrope of carbon under standard conditions (pressure and temperature). In graphite carbon atoms have sp2 hybridization, because of that graphite has ability to conduct electricity and heat.

2. The process by which a solid changes directly to a gas without first becoming a liquid is called c. sublimation.
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3. In the gaseous state d. halogens form diatomic covalent molecules.
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4. When hydrogen reacts with the active metals, it b. gains one electron.
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5. Different forms of the same element that have different properties because of different atom arrangements are called a. allotropes.
Carbon has many allotropes, but two most important are graphite and diamomd. Graphite has sp2 and diamond has sp3 hybridization of carbon atoms, because of that graphite conduct electricity and diamond not.

6. At room temperature, most metals are b. solids.
Most metals have strong metallic bond, because strong electrostatic attractive force between valence electrons (metals usually have low ionization energy and lose electrons easy) and positively charged metal ions.
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#1: At STP, how many molecules of nitrogen gas are in 22.4 L?

A. 6.022 × 10^22

B. 6.022 × 10^23

C. 6.022 × 10^24

D. 6.022 × 10^25

**my answer: B

is that right?? @aaronq :)

Answers

At STP, 1 mol = 22.4

1 mol = 6.022 X 10^ 23

so your answer is right it is B 6.022 X 10^ 23

In the reaction of aluminum bromide with ionized sodium bromide which compoiund is the lewis acid

Answers

The answer is A) Aluminum Bromide 
hope this helps :)

Answer:

Aluminium bromide

Explanation:

Thinking process:

The aluminium bromide has the following structure:

[tex]AlBr_{3}[/tex]

The compound is a Lewis acid.

Aluminium bromide has a vacant p-orbital so it accepts a lone pair of electrons and acts as a Lewis acid.

Sodium bromide, on the other hand, donates electrons and acts as a Lewis base like this:

[tex]AlBr_{3} + Br^{-} = AlBr^{-} _{4}[/tex]

Thus, clearly the bromide ion is a base, and it donates electrons.

During surgery, a patient receives 6.0 pt of plasma. how many milliliters of plasma were given? express the volume in milliliters to two significant figures.

Answers

The patient received 2839.059mL.

Answer : The volume of plasma given to the patient were, [tex]2.8\times 10^{3}ml[/tex]

Explanation :

As we are given that a patient receives 6.0 pints of plasma. Now we have to calculate the volume in milliliters.

As we know that, 1 pints is equal to 473.176 milliliters.

As, 1 pints = 473.176 milliliters

So, 6.0 pints = [tex]\frac{473.176milliliters}{1pint}\times 6.0pints=2839.056milliliter[/tex]

The volume in milliliters to two significant figures is, [tex]2.8\times 10^{3}ml[/tex]

Therefore, the volume of plasma given to the patient were, [tex]2.8\times 10^{3}ml[/tex]

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b. the number of protons
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a. one is new and the other is old.
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c. their atomic masses are different.
d. more people would rather have one gold atom than a lot of gold?

Answers

b)The number of protons.
c) their atomic masses are different.
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