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3 years ago

How many grams of chromium are in 2.0 x 1024 atoms

Chemistry

1 answer:

Vaselesa [24]3 years ago

7 0

Answer: 173 g ( 0.17 kg in right accuracy)

Explanation: Amount in moles is n = N/Na = 2.0·10^24 / 6.022·10^23 (1/mol).

n = 3.32116 mol. M(Cr) = 52.00 g/mol and mass m = nM = 172.7 g

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1. Which of these is the basic unit of mass?

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1.)B 2.)C 3.)A 4.)B 5.)C

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3 years ago

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The molar heat of fusion of platinum (Pt) is 4.700 kcal/mol. How much heat must be added to 85.5 g of

zvonat [6]

Answer:

2.07 Kcal heat must be added to completely melt the platinum.

Explanation:

Given data:

Molar heat of fusion = 4.700 Kcal / mol

Mass of platinum = 85.5 g

Heat of fusion = ?

Solution:

Formula:

ΔH = n × molar heat of fusion

n = number of moles

Now we will calculate the number of moles:

Number of moles = mass / molar mass

Number of moles = 85.5 g /195.08 g/mol

Number of moles = 0.44 mole

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ΔH = 0.44 mol × 4.700 Kcal / mol

ΔH = 2.07 Kcal

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3 years ago

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In what step do you perform the steps of your experiment?

vladimir2022 [97]

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Part II. The molality of a solution is the number of moles of the solute that is dissolved in 1000 g of solvent. Using the value

Aleks [24]

Answer:

Explanation:

The molality of a solution, m is defined as the number of moles of the solute that is dissolved in 1 kg of solvent.

m = number of moles/kilogram of solvent

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3 years ago

one method for generating chlorine gas is by reacting potassium permanganate and hydrochloric acid. how many liters of Cl2 at 40

Ronch [10]

Answer: The volume of chlorine gas produced in the reaction is 2.06 L.

Explanation:

For potassium permanganate:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of potassium permanganate = 6.23 g

Molar mass of potassium permanganate = 158.034 g/mol

Putting values in above equation, we get:

$\text{Moles of potassium permanganate}=\frac{6.23g}{158.034g/mol}=0.039mol$

For hydrochloric acid:

To calculate the moles of hydrochloric acid, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of HCl = 6.00 M

Volume of HCl = 45.0 mL = 0.045 L (Conversion factor: 1 L = 1000 mL)

Putting values in above equation, we get:

$6.00mol/L=\frac{\text{Moles of HCl}}{0.045L}\\\\\text{Moles of HCl}=0.27mol$

For the reaction of potassium permanganate and hydrochloric acid, the equation follows:

$2KMnO_4+16HCl\rightarrow 2MnCl_2+5Cl_2+2KCl+8H_2O$

By Stoichiometry of the reaction:

16 moles of hydrochloric acid reacts with 2 moles of potassium permanganate.

So, 0.27 moles of hydrochloric acid will react with = $\frac{2}{16}\times 0.27=0.033moles$ of potassium permanganate.

As, given amount of potassium permanganate is more than the required amount. So, it is considered as an excess reagent.

Thus, hydrochloric acid is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

16 moles of hydrochloric acid reacts with 5 moles of chlorine gas.

So, 0.27 moles of hydrochloric acid will react with = $\frac{5}{16}\times 0.27=0.0843moles$ of chlorine gas.

To calculate the volume of gas, we use the equation given by ideal gas equation:

$PV=nRT$

where,

P = pressure of the gas = 1.05 atm

V = Volume of gas = ? L

n = Number of moles = 0.0843 mol

R = Gas constant = $0.0820\text{ L atm }mol^{-1}K^{-1}$

T = temperature of the gas = $40^oC=[40+273]K=313K$

Putting values in above equation, we get:

$1.05atm\times V=0.0843\times 0.0820\text{ L atm }mol^{-1}K^{-1}\times 313K\\\\V=2.06L$

Hence, the volume of chlorine gas produced in the reaction is 2.06 L.

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4 years ago