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2 years ago

Q4. The student started with 16.0 grams of NaCl, show the calculation for the percent error that

Chemistry

1 answer:

Vedmedyk [2.9K]2 years ago

5 0

Answer:

72.6% Error

Explanation:

% error = $\frac{Real-Measured}{Real} * 100$

$\frac{58.44-16}{58.44} *100= 72.6$

58.44 is the weight of NaCl

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Every atom's goal is to get ________ electrons in its valence shell.

sdas [7]

Every atom tends to form configuration of noble gas , with the 8 electrons in valence shell.

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3 years ago

A sample of 10.6 g of KNO3 was dissolved in 251.0 g of water at 25 oC in a calorimeter. The final temperature of the solution wa

finlep [7]

Answer:

36.55kJ/mol

Explanation:

The heat of solution is the change in heat when the KNO3 dissolves in water:

KNO3(aq) → K+(aq) + NO3-(aq)

As the temperature decreases, the reaction is endothermic and the molar heat of solution is positive.

To solve the molar heat we need to find the moles of KNO3 dissolved and the change in heat as follows:

Moles KNO3 -Molar mass: 101.1032g/mol-

10.6g * (1mol/101.1032g) = 0.1048 moles KNO3

Change in heat:

q = m*S*ΔT

Where q is heat in J,

m is the mass of the solution: 10.6g + 251.0g = 261.6g

S is specififc heat of solution: 4.184J/g°C -Assuming is the same than pure water-

And ΔT is change in temperature: 25°C - 21.5°C = 3.5°C

q = 261.6g*4.184J/g°C*3.5°C

q = 3830.87J

Molar heat of solution:

3830.87J/0.1048 moles KNO3 =

36554J/mol =

6 0

2 years ago

What is the product of a force and the time during which the force acts

ELEN [110]

Impulse is the product of a force and the time during which that force acts on a body.

7 0

3 years ago

A tank at is filled with of sulfur tetrafluoride gas and of sulfur hexafluoride gas. You can assume both gases behave as ideal g

dangina [55]

The question is incomplete, the complete question is:

A 7.00 L tank at $21.4^oC$ is filled with 5.43 g of sulfur hexafluoride gas and 14.2 g of sulfur tetrafluoride gas. You can assume both gases behave as ideal gases under these conditions. Calculate the mole fraction and partial pressure of each gas. Round each of your answers to significant digits.

Answer: The mole fraction of sulfur hexafluoride is 0.221 and that of sulfur tetrafluoride is 0.779

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

For sulfur hexafluoride:

Given mass of sulfur hexafluoride = 5.43 g

Molar mass of sulfur hexafluoride = 146.06 g/mol

Putting values in equation 1, we get:

$\text{Moles of sulfur hexafluoride}=\frac{5.43g}{146.06g/mol}=0.0372mol$

For sulfur tetrafluoride:

Given mass of sulfur tetrafluoride = 14.2 g

Molar mass of sulfur tetrafluoride = 108.07 g/mol

Putting values in equation 1, we get:

$\text{Moles of sulfur tetrafluoride }=\frac{14.2g}{108.07g/mol}=0.1314mol$

Total moles of gas in the tank = [0.0372+ 0.1314] mol = 0.1686 mol

Mole fraction is defined as the moles of a component present in the total moles of a solution. It is given by the equation:

$\chi_A=\frac{n_A}{n_A+n_B}$ .....(2)

where n is the number of moles

Putting values in equation 2, we get:

$\chi_{SF_6}=\frac{0.0372}{0.1686}=0.221$

$\chi_{SF_4}=\frac{0.1314}{0.1686}=0.779$

Hence, the mole fraction of sulfur hexafluoride is 0.221 and that of sulfur tetrafluoride is 0.779

7 0

2 years ago

Which of the subshells below do not exist due to the constraints upon the angular momentum quantum number?A) 2dB) 2sC) 2pD) all

Gnom [1K]

Answer:

Option A): Due to the constraints upton the angular momentum quantum number, the subshell 2d does not exist.

Explanation:

The angular momentum quantum number, identified with the letter l (lowercase L), number is the second quantum number.

This number identifies the shape of the orbital or kind of subshell.

The possible values of the angular momentum quantum number, l, are constrained by the value of the principal quantum number n: l can take values from 0 to n - 1.

So, you can use this guide:

Principal quantum Angular momentum Shape of the orbital

number, n quantum number, l

1 0 s

2 0, 1 s, p

3 0, 1, 2 s, p, d

Hence,

the subshell 2d (n = 2, l = 2) is not feasible.

2s (option B) is possible: n = 2, l = 0

2p (option C) is possible: n = 2, l = 1

7 0

3 years ago