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3 years ago

State why argon is used in the light bulb. Explain your answer in terms of the electronic structure of an argon atom.

1 answer:

5 0

Hi I need Help with this :
A swimming pool has an inlet pipe that can fill the empty pool in 12 hours with the drain is closed and the inlet pipe is closed the drain can empty the full pool in 20 hours. When the pool is empty how long will it take the inlet pipe to fill the pool drain if it is left open ?

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When of alanine are dissolved in of a certain mystery liquid , the freezing point of the solution is less than the freezing poin

LenaWriter [7]

The question is incomplete, the complete question is:

When 177. g of alanine $(C_3H_7NO_2)$ are dissolved in 800.0 g of a certain mystery liquid X, the freezing point of the solution is $5.9^oC$ lower than the freezing point of pure X. On the other hand, when 177.0 g of potassium bromide are dissolved in the same mass of X, the freezing point of the solution is $7.2^oC$ lower than the freezing point of pure X. Calculate the van't Hoff factor for potassium bromide in X.

Answer: The van't Hoff factor for potassium bromide in X is 1.63

Explanation:

Depression in the freezing point is defined as the difference between the freezing point of the pure solvent and the freezing point of the solution.

The expression for the calculation of depression in freezing point is:

$\Delta T_f=i\times K_f\times m$

$\Delta T_f=i\times K_f\times \frac{m_{solute}\times 1000}{M_{solute}\times w_{solvent}\text{(in g)}}$ ......(1)

When alanine is dissolved in mystery liquid X:

$\Delta T_f=5.9^oC$

i = Vant Hoff factor = 1 (for non-electrolytes)

$K_f$ = freezing point depression constant

$m_{solute}$ = Given mass of solute (alanine) = 177. g

$M_{solute}$ = Molar mass of solute (alanine) = 89 g/mol

$w_{solvent}$ = Mass of solvent = 800.0 g

Putting values in equation 1, we get:

$5.9=1\times K_f\times \frac{177\times 1000}{89\times 800}\\\\K_f=\frac{5.9\times 89\times 800}{1\times 177\times 1000}\\\\K_f=2.37^oC/m$

When KBr is dissolved in mystery liquid X:

$\Delta T_f=7.2^oC$

i = Vant Hoff factor = ?

$K_f$ = freezing point depression constant = $2.37^oC/m$

$m_{solute}$ = Given mass of solute (KBr) = 177. g

$M_{solute}$ = Molar mass of solute (KBr) = 119 g/mol

$w_{solvent}$ = Mass of solvent = 800.0 g

Putting values in equation 1, we get:

$7.2=i\times 2.37\times \frac{177\times 1000}{119\times 800}\\\\i=\frac{7.2\times 119\times 800}{2.37\times 177\times 1000}\\\\i=1.63$

Hence, the van't Hoff factor for potassium bromide in X is 1.63

7 0

3 years ago

Which of the following describes a chemical property of metal A,reacts with acid B, conducts electricity C,attracted to a magnet

gogolik [260]

Answer:

I belive its the acid anwser because it can make rust which is a chemical change

Explanation:

6 0

3 years ago

Read 2 more answers

How many molecules of hydrogen gas (Hz) are needed to produce 9.0 x 1023 molecules of H2O?

VashaNatasha [74]

Answer:

Explanation: Ammonia (NH3) is produced by the reaction of nitrogen gas and hydrogen gas. ... How many grams of fluorine gas are needed to produce 100.00g of AlF3? ... How many molecules of CO2 gas can be produced of 156.24g of benzene, ... (a) If 16.74.g of Fe and 9.0 9 of H2O are allowed to react, how many grams of products.

4 0

3 years ago

Use Dot and cross method to show the bonding of the atoms and state the number of atoms of each element present

goldfiish [28.3K]

Answer:

Check the attached one..I only draw the Dot method of Magnesium and Fluorine.. since i love chemistry ..Hope this helps you...Balance you have to do it yourself..If you didn't get the answer let me know in the comments..But you have try okay..

5 0

2 years ago

A 60.0 kg object is moving east at 8.00 m/s, and then slows down to 4.00 m/s. How much work was done?

Colt1911 [192]

Answer:

-1440J

Explanation:

Hello,

This question requires us to calculate the work done on a object to move it from point A to point B

Data

Mass = 60kg

Initial velocity (V1) = 8.0m/s

Final velocity (V2) = 4.0m/s

Workdone on an object is equal to force applied on the object to move it through a particular distance.

Work done = force × distance

Force (F) = mass × acceleration

Distance = s

F = Ma

Work done = M× a × s

But a = velocity (v) / time (t)

Work done = mvs / t

But velocity = distance/ time

Work done = mv × v/

Work done = mv²

Work done = ½mv²

Workdone = ½M(V2² - V1²)

Workdone = ½ × 60 (4² - 8²)

Work done = 30 × (16 - 64)

Workdone = 30 × (-48)

Work done = -1440J

Work done = -1.44kJ

The workdone on the object is equal to -1.44kJ

5 0

3 years ago