What's the molality of a solution with 120 g of NaCl and 30 kg of water?

It is often necessary to prepare a dilute solution from a more concentrated solution rather than starting from a solid and just

valina [46]

Answer:

Take 10.0mL of your original solution and dilute it to 100.0mL and then, take 5.0mL of this solution and dilute it in another flask to 100.0mL

Explanation:

The initial solution of 0.3g of Red dye in 100mL has a concentration of:

0.3g Red dye × (1mol / 869g) = 3.4x10⁻⁴ mol Red Dye in 100mL = 0.100L:

3.4x10⁻⁴ mol / 0.1L = 3.4x10⁻³M

As you want a 1.7x10⁻⁵M solution, you need to dilute your solution:

3.4x10⁻³M / 1.7x10⁻⁵M = 200 times

Having this in mind, you must find the dilutions you must make to achieve the 200 of dilution factor (<em>Dilution factor is how many times you dilute a solution from a concetrated form).</em>

If you dilute the original solution taking 10.0mL to 100.0mL you dilute the solution: 100.0mL / 10.0mL = <em>10 times.</em>

Now, you need to dilute this solution another 20 times to achieve the 10*20 = 200 times of dilution.

If you take 5.0mL of the last solution and dilute it to 100.0mL you are diluting the solution 100.0mL / 5.0mL = <em>20 times.</em>

The dilution is:

3.4x10⁻³M × (10.0mL / 100.0mL) × (5.0mL / 100.0mL) = 1.7x10⁻⁵M

Thus, to obtain the 1.7x10⁻⁵M solutionyou need to:

<h3>Take 10.0mL of your original solution and dilute it to 100.0mL and then, take 5.0mL of this solution and dilute it in another flask to 100.0mL</h3>

8 0

3 years ago

As pressure decreases so does boiling point. One reason astronauts wear space suits in space is because of the decreased pressur

PilotLPTM [1.2K]

First, we need to be aware that our blood is also a form of liquid.
So, when the astronaut is placed in within the environment that has decreased pressure, the temperature inside the astronaut's body will definitely increase but it won't cause the boiling effect like in water (it won't even break the arteries). But it could endanger the astronaut's life because it makes the blood unable to circulate properly due to unstable blood pressure

4 0

3 years ago

Read 2 more answers

A reaction is second order respect to the reactant A. If the reaction is 85% complete in 12 minutes, how long would it take for

AnnZ [28]

Answer:

e. 22s

Explanation:

Initial Concentration = 100

Final concentration = 15 ( Since the reaction is 85% complete)

Time = 12 minutes = 720 seconds

The integrated rate law for second order reactions is given as;

1 / [A] = (1 / [A]o) + kt

Making k subject of interest, we have;

kt = (1 / [A] ) - (1 / [A]o )

k = (1 / [A] ) - (1 / [A]o ) / t

k = [(1/ 15) - (1 / 100) ] / 720

k = (0.0667 - 0.01 ) / 720

k = 0.0567 / 720

k = 7.875e^-5

How long would it take for the reaction to be 15% complete?

Final concentration = 85 (Since the reaction would be 15% complete)

The integrated rate law for second order reactions is given as;

1 / [A] = (1 / [A]o) + kt

Making t subject of interest, we have;

kt = (1 / [A] ) - (1 / [A]o )

t = (1 / [A] ) - (1 / [A]o ) / k

t = [(1 / 85 ) - (1 / 100) ] / 7.875e^-5

t = (0.0117 - 0.01 ) / 7.875e^-5

t = 0.001765 / 7.875e^-5

t = 22.41 seconds

Corect option = E.

3 0

4 years ago

A tank with volume of 2.4 cu ft is filled with Methane to a pressure of 1500 psia at 104 degrees F. Determine the molecular weig

Soloha48 [4]

Explanation:

It is known that equation for ideal gas is as follows.

PV = nRT

The given data is as follows.

Pressure, P = 1500 psia, Temperature, T = $104^{o}F$ = 104 + 460 = 564 R

Volume, V = 2.4 cubic ft, R = 10.73 $psia ft^{3}/lb mol R$

Also, we know that number of moles is equal to mass divided by molar mass of the gas.

n = $\frac{mass}{\text{molar mass}}$

m = $n \times W$

= $0.594 \times 16.04$

= 9.54 lb

Hence, molecular weight of the gas is 9.54 lb.

We will calculate the density as follows.

d = $\frac{PM}{RT}$

= $\frac{1500 \times 16.04}{10.73 \times 564}$

= 3.975 $lb/ft^{3}$

Now, calculate the specific gravity of the gas as follows.

Specific gravity relative to air = $\frac{\text{density of methane}}{\text{density of air}}$

= $\frac{3.975 lb/ft^{3}}{0.0765 lb/ft^{3}}$

= 51.96

6 0

4 years ago

What is colligative property? why does theproperty changes the way that it does when the amount of solute is increased. State an

elena-14-01-66 [18.8K]

Colligative properties are those substances that depend on the number of substances in the solution, not in the identity of that substance. The property changes the way that it does when the amount of solute is increased because it enables the solute to be scattered more. For example, the freezing point of salt water is lower than that of the pure water due to the salt ions present in water.

6 0

3 years ago