What is the mass of kilogram of an object that wileight 50.0 in round your answer to the nearest tenth

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.

svp [43]

Q: A
according to this formula, we can get the mole fraction of water (n):
P(solu) = n Pv(water)
when we have Pv(solu) = 22.8 and Pv(water) = 23.8 so by substitution:
22.8 = n * 23.8
n= 0.958
- we need to get the moles of glucose:
moles of water = 500 g(mass weight) / 18 (molar weight)= 27.7 mol
n = moles of water / ( moles of water + moles of glucose)
0.958 = 27.7 / ( 27.7+ moles of glucose)
0.958 moles of glucose + 26.5 = 27.7
0.968 moles of glucose = 1.2
moles of glucose = 1.253 mol
∴ the mass of glucose = no.of glucose moles x molar mass
= 1.253 x 180 = 225.5 g
Q: B
here we also need to get n (mole fraction of water )by using this formula:
Pv(solu) = n Pv(water)
when we have Pv(solu)=132 & Pv(water)=150 so, by substition:
132= n * 150
n = 0.88
so, mole fraction of solution = 1 - 0.88 = 0.12
and we can get after that the moles of water = (mass weight / molar mass)
- no.moles of water = 85 g / 18 g/mol = 4.7 moles
- total moles in solution = moles of water / moles fraction of water
= 4.7 / 0.88 = 5.34 moles
∴ moles of the solution = total moles in solu - moles of water
= 5.34 - 4.7 = 0.64 moles solute
∴ the molar mass of the solute = mass weight of solute / no.of moles of solute
= 53.8 / 0.64 = 84 g/mole

Q: C

moles of urea (NH2)2 CO = mass weight / molar mass
= 4.49 g / 60 g /mol
= 0.07 mol
moles of methanol = mass weight / molar mass
= 39.9 g / 32 g/mol = 1.25 mol
moles fraction of methanol = moles of methanol / (moles of methanol + moles of urea )
moles fraction of methanol = 1.25 / ( 1.25+0.07) = 0.95
by substitution in Pv formula we will be able to get the vapour pressure of the solu :
Pv(solu) = n P°v
Pv(solu) = 0.95 * 89 mm Hg
∴Pv(solu) = 84.55 mmHg

7 0

3 years ago

I need help I know it isnt A

inna [77]

It is B. Thank you later please and do good on the test!

5 0

3 years ago

Read 2 more answers

a chemist adds of a calcium bromide solution to a reaction flask. calculate the mass in grams of calcium bromide the chemist has

mestny [16]

The mass of Calcium bromide added in the flask is 29.7 g.

<h3>What is Molarity? </h3>

Molarity is defined as the ratio of number of moles od solute to the number of volume of solution in litres.

Molarity = number of moles/ volume

<h3>Calculation of Moles</h3>

Number of moles = Molarity × volume

Given,

Molarity of Calcium bromide = 0.363 M

Volume of Calcium bromide = 410 mL

= 0.410L

By substituting all the value, we get

Number of moles = 0.363 × 0.410

= 0.148 mol

As we know that,

Molar mass of Calcium bromide = 199.89 g

Mole is defined as the given mass of substance to the molar mass of substance.

Given mass = Moles × Molar mass

= 0.148 × 199.89

= 29.75 g

= 29.7 g (significant digit)

Thus, we calculated that the mass of Calcium bromide added in the flask is 29.7 g.

learn more about Molarity:

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DISCLAIMER:

The above question is incomplete. Below is the complete question

A chemist adds 410.0mL of a 0.363 M calcium bromide solution to a reaction flask. calculate the mass in grams of calcium bromide the chemist has added to the flask. round your answer to 3 significant digits.

4 0

2 years ago

10. A 2.36-gram sample of NaHCO3 was completely decomposed in an

Airida [17]

Answer:

0.79 g

Explanation:

Let's introduce a strategy needed to solve any similar problem like this:

Apply the mass conservation law (assuming that this reaction goes 100 % to completion): the total mass of the reactants should be equal to the total mass of the products.

Based on the mass conservation law, we need to identify the reactants first. Our only reactant is sodium bicarbonate, so the total mass of the reactants is:

$m_r=m_{NaHCO_3}=2.36 g$

We have two products formed, sodium carbonate and carbonic acid. This implies that the total mass of the products is:

$m_p=m_{Na_2CO_3}+m_{H_2CO_3}$

Apply the law of mass conservation:

$m_r=m_p$

Substitute the given variables:

$m_{NaHCO_3}=m_{Na_2CO_3}+m_{H_2CO_3}$

Rearrange for the mass of carbonic acid:

$m_{H_2CO_3}=m_{NaHCO_3}-m_{Na_2CO_3}=2.36 g - 1.57 g=0.79 g$

8 0

3 years ago

I NEED HELP PLEASE,THANKS!

Yakvenalex [24]

Answer:

Covalent bonding

Explanation:

In covalent bonding, the electrons are shared to fill the octet rule (8 electrons in valence shell). CCl4 tends to do covalent bonding because the the 4 valence electrons are Carbon are shared with the Chlorine atoms so that each chlorine atom has a full octet and chlorine shares its electrons to fill the octet of carbon.

Also, since carbon and chlorine are both non-metal, non-metal things exhibit covalent bonding thus this is covalent bonding as well. Ionic boding is for metal and non metal pair where electrons are transferrred, in our case, electrons are shared, they are not transferred.

6 0

3 years ago