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2 years ago

Describe how this instrument works. Operation:

Chemistry

2 answers:

scoundrel [369]2 years ago

7 0

Answer:

its a telescope you see stars or plants

Explanation:

guapka [62]2 years ago

6 0

Answer:

Microscope

Explanation:

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A 51.24-g sample of Ba(OH)2 is dissolved in enough water to make 1.20 liters of solution. How many mL of this solution must be d

g100num [7]

Answer:

0.40 L

Explanation:

Calculation of the moles of $Ba(OH)_2$ as:-

Mass = 51.24 g

Molar mass of $Ba(OH)_2$ = 171.34 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{51.24\ g}{171.34\ g/mol}$

$Moles= 0.2991\ mol$

Volume = 1.20 L

The expression for the molarity is:

$Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}$

$Molarity=\frac{0.2991\ mol}{1.20\ L}=0.24925\ M$

Thus,

Considering

$Molarity_{working\ solution}\times Volume_{working\ solution}=Molarity_{stock\ solution}\times Volume_{stock\ solution}$

Given that:

$Molarity_{working\ solution}=0.100\ M$

$Volume_{working\ solution}=1\ L$

$Volume_{stock\ solution}=?$

$Molarity_{stock\ solution}=0.24925\ M$

So,

$0.100\ M\times 1\ L=0.24925\ M\times Volume_{stock\ solution}$

$Volume_{stock\ solution}=\frac{0.100\times 1}{0.24925}\ L=0.40\ L$

<u>The volume of 0.24925M stock solution added = 0.40 L </u>

6 0

3 years ago

How many moles of methane (CH4) could be made from 4.6 moles of hydrogen?

DENIUS [597]

Answer:

Number of moles of methane form = 2.3 mol

Explanation:

Given data:

Number of moles of Hydrogen = 4.6 mol

Number of moles of methane form = ?

Solution:

Chemical equation:

C + 2H₂ → CH₄

Now we will compare the moles of methane with hydrogen from balance chemical equation.

H₂ : CH₄

2 : 1

4.6 : 1/2×4.6 = 2.3 mol

Form 3.6 moles of hydrogen 2.3 moles of methane can be formed.

6 0

3 years ago

What is mb for CH3NH2….

drek231 [11]

Answer:

A.) $K_b = \frac{[CH_3NH_3^+][OH^-]}{[CH_3NH_2]}$

Explanation:

The general Kb expression is:

$K_b = \frac{[HA][OH^-]}{[A^-]}$

In this equation

-----> Kb = equilibrium constant

-----> [HA] = acid

-----> [A⁻] = base

Since liquids are not included in equilibrium expressions, H₂O should not be present. The products are in the numerator while the reactant are in the denominator. In this reaction, CH₃NH₂ is acting as a base and CH₃NH₃⁺ is acting as an acid.

As such, the expression is:

$K_b = \frac{[CH_3NH_3^+][OH^-]}{[CH_3NH_2]}$

7 0

2 years ago

Calculate the vapor pressure of a solution made by dissolving 11.1 g Ca(OH)2 in 1 102 g of water at 25 °C. Vapor pressure of pur

Levart [38]

Answer:

23.15 mmHg.

Explanation:

To solve this question you need to understand that part of Raoult's law in your Chemistry textbook. So, let us delve right into the solution of the question.

We are given parameters such as the mass of Ca(OH)2 to be = 11.1 grams, mass of solvent = 102 grams, the Vapor pressure of pure water= 23.76 mm Hg, temperature = 25°C and vapour pressure of the solution= ??.

The molar mass of Ca(OH)2= 74 g/mol.

The first thing to do is to find the number of moles of Ca(OH)2 and that of water from the formula below;

Mass/ molar mass = Number of moles.

===> Number of moles, n= 11.1/ 74.

Number of moles = 0.15 moles Ca(OH)2.

===> Number of moles, n= 102/ 18.

Number of moles, n= 5.67 moles of water.

Next, we add the two moles together to find the solvent mile fraction since vapour pressure is proportional to mole fraction.

Then;

0.15 + 5.67 = 5.82.

Therefore, 5.67/ 5.82= 0.97.

Hence the vapor pressure of a solution = 0.97 × 23.76.

vapor pressure of a solution = 23.15 mmHg.

4 0

3 years ago

Read 2 more answers

1: The atomic number of an atom is equivalent to which of the following?

IrinaVladis [17]

I think the correct answer among the choices presented above is option C. The <span>atomic number of an atom is equivalent to the number of protons in the nucleus. For a neutral atom, it is also the number of electrons since in a neutral atom protons and electrons are present in equal number.</span>

7 0

3 years ago