In the lab, a student adds 4.5 g of sodium chloride (NaCl) to 100.0 g of water. Calculate the molality of the solution.

Answers

Answer 1

Answer:

0.77mol/Kg.

Explanation:

The following data were obtained from the question:

Mass of NaCl = 4.5g

Mass of water = 100g.

Molality =...?

Next, we shall determine the number of mole in 4.5g of NaCl. This can be obtained as follow:

Mass of NaCl = 4g.

Molar mass of NaCl = 23 + 35.5 = 58.5g/mol

Number of mole NaCl =..?

Mole = Mass /Molar Mass

Number of mole of NaCl = 4.5/58.5

Number of mole of NaCl = 0.077 mole.

Next, we shall convert 100g of water to kilograms. This is illustrated below:

1000g = 1kg

Therefore, 100g = 100/1000 = 0.1Kg.

Finally, we can determine the molality of the solution as follow:

Molality is simply defined as the mole of solute per unit kilogram of solvent (water). Mathematically, it is represented as:

Molarity = mole of solute / kg of solvent

Mole of solute, NaCl = 0.077 mole

Kg of solvent = 0.1kg

Molality = 0.077mol/0.1kg

Molality = 0.77mol/Kg

Answer 2

The molarity of the solution is 0.77mol/Kg.

Calculation of the molarity of the solution:

Since

Mass of NaCl = 4.5g

Mass of water = 100g.

Here,

Mass of NaCl = 4g.

Molar mass of NaCl = 23 + 35.5 = 58.5g/mol

Now

Mole = Mass /Molar Mass

= 4.5/58.5

= 0.077 mole.

Now

1000g = 1kg

So,

100g = 100/1000 = 0.1Kg.

Now

Molarity = mole of solute / kg of solvent

Mole of solute, NaCl = 0.077 mole

Kg of solvent = 0.1kg

So,

Molality = 0.077mol/0.1kg

= 0.77mol/Kg

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Related Questions

Calculate the percentage of all elements in Fel(OH)3

Please help, I will mark the answer with brainlist...​

Answers

Answer: 30.06% is your answer.

I hope this helps.

Stay safe and have a good day :D

How are ironic bonds and covalent bonds different and how are they different?

Answers

Ionic bonds are forces that hold together electrostatic forces of attractions between oppositely charged ions. Ionic bonds have an electronegativity difference greater than or equal to 2. Covalent bonds have an electronegativity difference that is less than 2.

A 315-mL bag of potato chips is packaged at sea level (1.00 atm) where the temperature is 25oC. If this bag of chips is transported to Denver (where the pressure is 0.775 atm and the temperature is 18oC), what will the new volume of the bag be?

Answers

Answer:

THE NEW VOLUME AT A PRESSURE OF 0.775 atm AND TEMPERATURE OF 18 °C IS 0.397 L

Explanation:

Using the combined gas equation

P1V1/T1 = P2V2/ T2

P1 = 1 atm

VI = 315 mL = 315 / 1000 L = 0.315 L

T1 = 25°C  25 + 273 K = 298 K

P2 = 0.775 atm

T2 = 18 °C = 18 + 273 K = 291 K

V2 = Unknown

Substituting the values into the equation, we obtain:

V2 = P1V1 T2/ P2 T1

V2 = 1 * 0.315 * 291 / 0.775 * 298

V2 = 91.665 / 230.95

V2 = 0.3969 L

The new volume at the given change in conditions is 0.397 L

how much volume do the gas molecules take up in an inflated balloon

Answers

Answer:

The volume of a gas is determined by the volume of the container it is in. Gases take the shape of their container and the volume of the container....

Explanation:

What happens to the volume or size of a balloon as it rises in the air?

When a balloon goes up higher in the air, its size will increase. Since there's less air in the upper atmosphere, there's less stuff pushing back on the balloon, and hence the pressure is lower, which allows the balloon to expand.

Is pressure inside a balloon greater?

The pressure inside the balloon is higher than the pressure on the outside. ... And the direction of airflow is always from higher to lower pressure. If the pressure was same then there would be no airflow and if the pressure outside was higher , air will flow from outside to the inside of the balloon.

What is the relationship between volume and pressure?

Boyle's law is a gas law, stating that the pressure and volume of a gas have an inverse relationship. If volume increases, then pressure decreases and vice versa, when temperature is held constant. Therefore, when the volume is halved, the pressure is doubled; and if the volume is doubled, the pressure is halved.

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It depends on how many volume the container is in

How many liters of hydrogen gas is produced from 3.712 g of magnesium with 104.2ml of 1.385 mol/L HCL (aq) at SATP? Please show your work and explain it. I really need help with this question, it's on one of my quizzes.

Answers

Answer:

[tex]V=1.61L[/tex]

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

[tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]

Next, we compute the reacting moles of each reactants:

[tex]n_{Mg}=3.712gMg*\frac{1molMg}{24.305 gMg}=0.153molMg[/tex]

[tex]n_{HCl}=1.385\frac{molHCl}{L}*0.1042L=0.144molHCl[/tex]

Then, as magnesium and hydrohloric acid are in a 1:2 molar ratio 0.153 moles of magnesium will completely react with 0.306 moles of hydrochloric acid yet we only have 0.144 moles, therefore, limiting reactant is hydrochloric acid. Thus, we compute the produced moles of hydrogen:

[tex]n_{H_2}=0.144molHCl*\frac{1molH_2}{2molHCl} =0.072molH_2[/tex]

Finally, we use the ideal gas equation with T=298K and 1atm (STP conditions) to compute the liters of hydrogen gas:

[tex]PV=nRT\\\\V=\frac{nRT}{P}=\frac{0.072mol*0.082\frac{atm*L}{mol*K}*273K}{1atm}\\ \\V=1.61L[/tex]

Best regards.

What is meant by “normal” when you are asked for normal boiling and melting points?

Answers

Answer:

Normal boiling point is the temperature at which a liquid boils at 1 atmosphere of pressure.

Explanation:

What are the 5R principles of which we can make a difference in our environment?

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Answer:

The 5R's are Reuse, Reduce, Recycle, Repair and Recover.

Please Help In need of chemistry help

The reaction CH4 + Br2 → CH3Br + HBr is an example of

1.Addition
2.Polymerization
3.Substitution
4.Hydrogenation

Answers

it’s an example of substitution

Which set of phrases best lists the characteristics of asexual reproduction?

one parent, offspring are not identical to the parent

one parent, offspring are identical to the parent

two parents, offspring are not identical to the parents

two parents, offspring are identical to the parents
I need this answer fast ASAP.

Answers

Answer:

one parent, offspring are identical to the parent

Explanation:

Answer:

one parent, offspring are identical to the parent

Explanation:

asexual reproduction is a form of reproduction that does not require two gametes to fuse. Asexual reproduction results in offspring that are known as stable clones, meaning that their genetic makeup is stable and doesn't change between generations

What is the normal boiling point of of a solution containing 64.5g of non volatile quinoline ( MW 129 ) in 500 g of benzene when the normal boiling point is 80.10 and KB = 2.50

Answers

Answer:

THE NORMAL BOILING POINT OF A SOLUTION CONTAINING 64.5 g OF QUINOLINE IN 500 g OF BENZENE IS 82.6 C

Explanation:

Boiling point = old boiling point + molarity * boiling point constant (Kb)

First, you calculate the number of moles of quinoline in the solution

number of moles = mass / molar mass

Since the molar mass of quinoline has been given as 129 g/mol

number of moles = 64.5 g / 129 g/mol

number of moles = 0.5 moles.

Next is to determine the molarity:

molarity = number of moles of solute / kilogram of solvent

molarity = 0.5 moles / 500/1000 kg

molarity = 0.5 / 0.5

molarity = 1 M

The new boiling point can then be calculated using the formula:

B. P = old B.P + Kb * molarity

B.P = 80.10 + 2.50 * 1

B.P = 80.10 + 2.50

B.P = 82.6 degree celsius

Triangle W Z Y is cut by bisector Z X. The lengths of sides Z W and Z Y are congruent. ZX bisects ∠WZY. If the measure of ∠YXZ is (6m – 12)°, what is the value of m?

Answers

Answer:

m = 17

Explanation:

From the question we were given that

Triangle WZY is bisected by ZX; ZW = ZY

∠YXZ = (6m – 12)°

Based on the characteristics of the triangle, we see that triangle WYZ is an isosceles triangle (that is, triangle WXZ is equal to triangle YXZ)

<YXZ = <WXZ = 90°

Using ∠YXZ  = (6m – 12)°

We have:

(6m – 12)° =  90°

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m = 17

We therefore see that m is equal to 17

Answer:

B: 17

Explanation:

to well
Which of the
of the following is a way to use
water economically
a construction of bewris
b Rainwater harvesting
c Drup irrigation
d Infitration

Answers

Answer:

c Drup irrigation

Explanation:

Hope it helps you.

Plz mark as brainliest plz.

You make an iron (II) sulfate solution with a molarity of 2.1 M. If the solution is 500 mL total, how many grams of iron (II) sulfate is that?

Answers

Answer:

Explanation:

2.1>1000

?>500

(500×2.1)÷1000=1.05moles

Mass= molesx molar mass

1.05×(56+32+(16×4))

1.05×152=159.6g

Which body system processes food into a useable source of energy?

Answers

Answer:

Glucose, found in the food animals eat, is broken down during the process of cellular respiration into an energy source called ATP. When excess ATP and glucose are present, the liver converts them into a molecule called glycogen, which is stored for later use.

The digestive system processes food into a usable source of energy.

What is the molarity of a solution that contains 2 moles of KCl in 4 L of solution? a 2.0 M b 0.5 M c 0.25 M d 8.0 M

Answers

Answer:

A.) 2.0 M

Explanation:

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Identify what is in that photo please!! (10 pts)

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Answer:

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The top one would be the correct answer

Diagrams, tables, and graphs are used by scientists to

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Answer:

Since most of the data scientist collect is quantitative, data tables and charts are usually used to organize the information • Graphs are created from data tables • hope that helps love!

to the
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DONE

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Answer

what do you mean?

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im confused

Answer:

Sorry. I don't understand

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A. K2O

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C. MgO

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Answers

Answer:

B

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its an acidic oxide, it disolves in water to form carbonic acid which is an acid

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Answer:

im pretty sure they heat up

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as they use energy to go from solid to liquid to gas, they need heat to do so as they have a melting and boiling point

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1
2
3
4​

Answers

Answer:

3

Explanation:

Phosphorous valence is 5. so to get stable electronic configuration it has to gain 3 more electrons to its outer shell

Answer:

3

Explanation:

luckily, every phosphorus atom is looking to gain 3 electrons. It's a perfect match. But something to notice though, look how they have a bond with six electrons. That is called triple bond.

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What are the two ways that humans lose heat? PLS help thank you!

Answers

Answer:

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Explanation:

Evaporation of water from your skin if it is wet (sweating). ...

Radiation (similar to heat leaving a woodstove).

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Answers

Answer:

Heat travels faster in solids.

Heat travels slower in gases.

Explanation:

The state of matter in which heat travels in fastest way is solid and in gaseous state heat travels in slowest way.

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Heat transfer is a process in which heat can travel from one body to another body or from high temperature to low temperature.

In solid state heat will travel in the fastest way because molecules are arranged very close to each other and heat will travel through conduction process. And in gaseous state heat will travel with slowest way as molecules are arranged in very distance.

Hence in solid, heat travels in fastest way and in gases heat travels in slowest way.

To know more about heat conduction, visit the below link:

https://brainly.com/question/1121702

what is chemistry? ​

Answers

Answer:the branch of science which examines the material of the universe and changes that these materials undergo

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Answers

Answer:

spring constant. acceleration due to gravity. distance from a given position. amount of matter in the object.

Explanation:

hope this helps you :)

Answer:

spring constant

Explanation:

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Answers

Lithium=li

Iron=Fe

Helium=He

I don't say u must have to mark my ans as brainliest but if u think it has really helped u plz don't forget to thank me....

Answer:

lithium symbol=li helium= he and iron =i

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Answer:

Ribose

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This is the pentose sugar found in RNA commonly.

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Answers

Answer:

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