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Reil [10]
2 years ago
13

A skateboarder coasts a distance of 20 meters in 4 seconds. What is the person's speed?

Chemistry
1 answer:
yKpoI14uk [10]2 years ago
5 0

Answer:

5

Explanation:

20/4

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You wish to make a 0.375 M hydroiodic acid solution from a stock solution of 6.00 M hydroiodic acid. How much concentrated acid
cluponka [151]

We need to add 2.09 mL of concentrated acid to obtain 75 mL of 0.335 M HBr solution.

You are performing a dilution of HBr going from a concentration of 12M to 0.335M, and you want to end up with a final volume of 75 ml of the dilute solution.

Consider the dilution formula: M1V1 = M2V2.

The basis behind this formula is that the number of moles of the acid before and after the dilution must remain constant.

M1 = the molarity of the stock solution,

M2 = the molarity of the diluted solution,

V2 = the final volume of the diluted solution.

In this case, we need to determine V1, which is the volume of the stock solution used to prepare the diluted sample. With this knowledge, we can plug our numbers into the equation and we obtain the following:

(12 mol/L)*V1 = (0.335mol/L)*(0.075L).

Keeping in mind that molarity is the moles of a substance in one liter of solution, we will use mol/L instead of M. By doing this, we are reminded that in order to use this equation, we must convert 75 mL into units of liters.

After rearranging the equation and solving for V1, we find that V1 = 0.00209L.

Finally, we must convert back from liters to mL by multiplying the final answer by 1000.

This way we end up with V1 = 2.09 mL.

This means that we need to add 2.09 mL of concentrated acid to obtain 75 mL of 0.335 M HBr solution.

Learn more about molarity here: brainly.com/question/23243759

#SPJ4

3 0
2 years ago
A single-effect evaporator is concentrating a feed of 9072 kg/h of a 10 wt % solution of NaOH in water at temperature of 288.8 K
Aloiza [94]

Answer:

a) steam used = 8440 kg/hr

b)  Because as per calculation done in a), Steam is sufficient to evaporate 7257.6 kg/hr water from feed. Since feed is less than this amount, therefore whole water will be evaporated and 100% solid product will be obtained in bottom collection

Explanation:

Saturated steam pressure = 42KPag=1.42 bar

From steam table, Steam temperature = 110 C

Latent heat of this steam = 2230 KJ/kg

Process side pressure = 20 Kpaa = .2 bar

Water latent heat at this Pressue = 2360 KJ/kg

Water boiling Point at this Pressure =60 C

Feed Inlet temperature = 15.6 C

Total Heat required = Heat required to rise feed temperature from 15.6 to 60 degree C + Evaporation of water to concentrate the feed

Total Water evaporation required = 9072*(100-10)/100-9072*.1/.5*.5=7257.6 Kg/hr

Specific heat of feed assumed = 4.2 KJ/kg/K

=> Total heat required = 9072*4.2*(60-15.6)+7257.6*2360=18819682 KJ/hr

LMTD = ((110-60)-(110-15.6))/LN((110-60)/(110-15.6))=69.8 C

U, Overall Heat transfer coefficient = 1988 W/m2/K

Total heat required = U*A*LMTD

=> Area required of evaporator, A=18819682 *1000/3600/1988/59.8=44 m2

Steam used = 18819682/2230=8440 kg/hr

Energy required to condense vaporised feed = 7257.6*2360=17127936 KJ/hr

=> Steam efficiency = (18819682-17127936)/18819682=9%

b) Because as per calculation done in a), Steam is sufficient to evaporate 7257.6 kg/hr water from feed. Since feed is less than this amount, therefore whole water will be evaporated and 100% solid product will be obtained in bottom collection

6 0
3 years ago
Read 2 more answers
How do thermal energy and intermolecular forces behave with each other?
julia-pushkina [17]
When there is more thermal energy, there are less intermolecular forces. I hope this answers your question ☺️☺️
5 0
3 years ago
Which of the following chemical formulas is a compound?<br> a. Ne<br> b. NaCl<br> c. Cu<br> d. C
qaws [65]

NaCl beacuse it has 2 elements combined

4 0
3 years ago
Read 2 more answers
Calculate the amount in moles and grams of KMnO4 present in 3dm^3 of 0.25M​
Stels [109]

Answer:

Number of moles   = 0.75 mol

Mass = 118.5 g

Explanation:

Given data:

Number of moles of KMnO₄ = ?

Mass in gram = ?

Molarity of KMnO₄ = 0.25 M

Volume of KMnO₄ solution = 3 dm³ (3 L)

Solution:

Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.

Formula:

Molarity = number of moles  / L of solution

0.25 M = number of moles / 3 L

Number of moles   = 0.25 M× 3 L

            M = mol/L

Number of moles   = 0.75 mol

Mass in gram:

Mass = number of moles × molar mass

Mass = 0.75 mol × 158 g/mol

Mass = 118.5 g

5 0
2 years ago
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