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3 years ago

Which of these is an example of a physical change?

Chemistry

1 answer:

Sonja [21]3 years ago

7 0

Answer: a) sugar dissolving in warm water

Explanation: I think this is the best answer because physical changes are usually reversible and no chemical action occurs

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A river with a flow of 50 m3/s discharges into a lake with a volume of 15,000,000 m3. The river has a background pollutant conce

spin [16.1K]

Explanation:

The given data is as follows.

Volume of lake = $15 \times 10^{6} m^{3}$ = $15 \times 10^{6} m^{3} \times \frac{10^{3} liter}{1 m^{3}}$

Concentration of lake = 5.6 mg/l

Total amount of pollutant present in lake = $5.6 \times 15 \times 10^{9} mg$

= $84 \times 10^{9}$ mg

= $84 \times 10^{3}$ kg

Flow rate of river is 50 $m^{3} sec^{-1}$

Volume of water in 1 day = $50 \times 10^{3} \times 86400 liter$

= $432 \times 10^{7}$ liter

Concentration of river is calculated as 5.6 mg/l. Total amount of pollutants present in the lake are $2.9792 \times 10^{10} mg$ or $2.9792 \times 10^{4} kg$

Flow rate of sewage = $0.7 m^{3} sec^{-1}$

Volume of sewage water in 1 day = $6048 \times 10^{4}$ liter

Concentration of sewage = 300 mg/L

Total amount of pollutants = $1.8144 \times 10^{10} mg$ or $1.8144 \times 10^{4}kg$

Therefore, total concentration of lake after 1 day = $\frac{131936 \times 10^{6}}{1.938 \times 10^{10}}mg/ l$

= 6.8078 mg/l

$k_{D}$ = 0.2 per day

$L_{o}$ = 6.8078

Hence, $L_{liquid}$ = $L_{o}(1 - e^{-k_{D}t}$

$L_{liquid}$ = $6.8078 (1 - e^{-0.2 \times 1})$

= 1.234 mg/l

Hence, the remaining concentration = (6.8078 - 1.234) mg/l

= 5.6 mg/l

Thus, we can conclude that concentration leaving the lake one day after the pollutant is added is 5.6 mg/l.

5 0

4 years ago

Ba(NO3)2<br> What’s the atomic mass

Ahat [919]

Answer:

261.337 g/mol

Explanation:

3 0

3 years ago

The percent yield of a chemical reaction is valuable to many industries. Low percent yields can result in the loss of large amou

aev [14]

Using accurate measurements, using pure chemicals and performing the reaction under the most ideal conditions is important to get a valuable percent yield.

<h3>How we calculate the percent yield?</h3>

Percent yield of any chemical reaction is define as the ratios of the actual yield to the theoretical yield of the product and multiply by the 100.

To get the high percent yield or actual yield of any reaction, we have to perform the reaction under ideal condition because if we not use the standard condition then we get the low rate of reaction. Reactants should be present in the pure form as impurity make unwanted products and reduce the productivity of main product and accurate amount of reactants also important for the spontaneous reaction.

Hence, options (a), (b) & (c) are correct.

To know more about percent yield, visit the below link:

brainly.com/question/8638404

7 0

2 years ago

Q 9 The table lists the steps to clean water for drinking purpose. 1. Adding chlorine tablets to the water.2. Pouring the water

love history [14]

Answer:

1 and 2

Explanation:

when we r adding chlorine to water

the water is clean

8 0

3 years ago

Can I find the state of Ca3N2 using the solubility rules? If so how because there is no Nitride in the solubility tables, I don'

Mamont248 [21]

Answer:

The day I was in the shower and I will be there at remove the day I was in the shower and I will be there at remove the day to see if you have any questions please feel free to contacts and the day I was in the shower and I will be there at remove the day I was in the shower and I will be there at remove the days of the week are you

8 0

3 years ago

Read 2 more answers