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2 years ago

what is the boiling point of the solution resulted from the dissolving of 32.5g of NaCl in 250.0g of water?

Chemistry

1 answer:

suter [353]2 years ago

8 0

Answer:

The boiling point of this solution is 102.28 °C

Explanation:

Step 1: Data given

Mass of Nacl = 32.5 grams

Molar mass of NaCl = 58.45 g/mol

Mass of Water = 250 grams

Boiling point of water = 100°C

Step 2: Calculate number of moles

Number of moles = mass of NaCl / Molar mass of NaCl

Number of moles = 32.5 grams /58.45 g/mol = 0.556 moles

Step 3: Calculate molality

Molality = Number of moles / mass of water

Molality = 0.556 moles / 0.250 kg of water

Molality = 2.224 molal

NaCl releases twice as many moles of ions, the total molality of this solution is also twice: 4.448 molal

Step 4: Calculate boiling point

dT =( 0.512 C / molal)*4.448 molal)

dT = 2.28

The boiling point of this solution is 100 °C + 2.28 °C = 102.28 °C

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What mass of al is required to completely react with 25.0 grams of mno2?

horsena [70]

Mass of MnO2 = 25 g
The reaction would be 3MnO2 + 4Al --> 3Mn(s) + 2Al2O3
Molar mass of Al = 26.982 g/mol
Molar mass of MnO2 = 54.938 + 2(15.999) = 86.936 g/mol
Calculating the moles = 25 / 86.936 = 0.2876 mol.
Mole ratio MnO2 and Al considering the equation = 3 mol of MnO : 4 mol of Al
Calculating the moles of Al = 0.2876 mol MnO2 x (4 mol of Al / 3 mol of MnO)
Number of moles of Al = 0.3834
Getting the mass in grams as asked = 0.3834 mol x 26.982 g/mol = 10.34 grams.

6 0

2 years ago

Read 2 more answers

Consider the reaction. X ( g ) + Y ( g ) − ⇀ ↽ − Z ( g ) K p = 1.00 at 300 K In which direction will the net reaction proceed fo

marta [7]

Answer:

Explanation:

We have in this question the equilibrium

X ( g ) + Y ( g ) ⇆ Z ( g )

With the equilibrium contant Kp = pZ/(pX x pY)

The moment we change the concentration of Y, we are changing effectively the partial pressure of Y since pressure and concentration are directly proportional

pV = nRT ⇒ p = nRT/V and n/V is molarity.

Therefore we can calculate the reaction quotient Q

Qp = pZ/(pX x pY) = 1/ 1 x 0.5 atm = 2

Since Qp is greater than Kp the system proceeds from right to left.

We could also arrive to the same conclusion by applying LeChatelier´s principle which states that any disturbance in the equilibrium, the system will react in such a way to counteract the change to restore the equilibrium. Therefore, by having reduced the pressure of Y the system will react favoring the reactants side increasing some of the y pressure until restoring the equilibrium Kp = 1.

4 0

2 years ago

8. What is the molecular formula of a compound if 0.50 moles of it contains 0.50

11Alexandr11 [23.1K]

Answer:

Explanation:

3 0

2 years ago

Calculate the number of hydrogen atoms in 33.0 g CH4

Elena-2011 [213]

Answer:

The number of hydrogen atoms is 4.96x10²⁴.

Explanation:

The number of atoms can be found with the following equation:

$n = N*\eta_{H}$

Where:

N: is the Avogadro's number = 6.022x10²³ atoms/mol

η: is the number of moles of hydrogen

n: is the number of hydrogen atoms

First, we need to find the number of hydrogen moles. The number of moles of CH₄ is:

$\eta_{CH_{4}} = \frac{m}{M}$

Where:

m: is the mass of methane = 33 g

M: is the molar mass of methane = 16.04 g/mol

$\eta_{CH_{4}} = \frac{33 g}{16.04 g/mol} = 2.06 mol$

Now, since we have 4 hydrogen atoms in 1 mol of methane, the number of moles of hydrogen is:

$\eta_{H} = 2.06\: mol\: CH_{4}*4 \frac{mol\: H}{mol \: CH_{4}} = 8.24 mol$

Hence, the number of hydrogen atoms is:

$n = N*\eta_{H} = 6.022 \cdot 10^{23} \: atoms/mol*8.24 mol = 4.96 \cdot 10^{24} atoms$

Therefore, the number of hydrogen atoms is 4.96x10²⁴.

I hope it helps you!

3 0

2 years ago

The process where a substance reacts with oxygen

daser333 [38]

Answer:

The process where substance react with oxygen is called combustion.

Explanation:

When substance react with oxygen combustion is occur. The substance which burned is called fuel and in this process large amount of heat is released to the surrounding. It is exothermic process.

For example:

4Li + O₂ → 2Li₂O

2Mg + O₂ → 2MgO

S + O₂ → SO₂

The product which is formed as a result of combustion reaction are called oxides.

In given examples we can see that lithium, magnesium and sulfur react with oxygen and product formed is oxides of respective elements such as lithium oxide ( Li₂O), magnesium oxide (MgO) and sulfur oxide ( SO₂ ).

3 0

3 years ago