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3 years ago

Calculate the mass in grams of each sample. 4.88x10^20 H2O2 molecules

Chemistry

1 answer:

AleksAgata [21]3 years ago

5 0

4.88x10^20 H2O2 molecules

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A tank contains 90 kg of salt and 2000 L of water. Pure water enters a tank at the rate 6 L/min. The solution is mixed and drain

sashaice [31]

Answer:

a) 90 kg

b) 68.4 kg

c) 0 kg/L

Explanation:

Mass balance:

$-w=\frac{dm}{dt}$

w is the mass flow

m is the mass of salt

$-v*C=\frac{dm}{dt}$

v is the volume flow

C is the concentration

$C=\frac{m}{V+(6-3)*L/min*t}$

$-v*\frac{m}{V+(6-3)*L/min*t}=\frac{dm}{dt}$

$-3*L/min*\frac{m}{2000L+(3)*L/min*t}=\frac{dm}{dt}$

$-3*L/min*\frac{dt}{2000L+(3)*L/min*t}=\frac{dm}{m}$

$-3*L/min*\int_{0}^{t}\frac{dt}{2000L+(3)*L/min*t}=\int_{90kg}^{m}\frac{dm}{m}$

$-[ln(2000L+3*L/min*t)-ln(2000L)]=ln(m)-ln(90kg)$

$-ln[(2000L+3*L/min*t)/2000L]=ln(m/90kg)$

$m=90kg*[2000L/(2000L+3*L/min*t)]$

a) Initially: t=0

$m=90kg*[2000L/(2000L+3*L/min*0)]=90kg$

b) t=210 min (3.5 hr)

$m=90kg*[2000L/(2000L+3*L/min*210min)]=68.4kg$

c) If time trends to infinity the division trends to 0 and, therefore, m trends to 0. So, the concentration at infinit time is 0 kg/L.

6 0

3 years ago

Using Models to Answer Questions About Systems

viva [34]

1A: The legs can be a adjusted, as well as the sand can be swapped out. It’s a very good design for running multiple tests.
1B: He could add books or something under the front or back legs in order to increase/decrease the incline, therefore imitating the hypothesis.
1C: He can change out the sand grains to finer ones, or coarser ones, and record his results of each test.
2: If he sets the model at a steep incline and tests it with coarse sand and fine sand, seeing which one makes a narrower, deeper hole.

5 0

3 years ago

Read 2 more answers

Which can occur during a physical change? (Select all that apply.)

koban [17]

Answer:

the shape of a piece of matter can change

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3 years ago

3. 200 ml of 0.2 M HCl is neutralized with 0.1 M

algol [13]

Answer:

a. 0.1 M

Explanation:

By definition, half neutralization is the point at which half of the acid has been neutralized.

The neutralization reaction that you are studying is the acid-base reaction:

HCl (aq) + NaOH (aq) → NaCl(aq) + H₂O (aq)

Then, since the starting molarity of the acid (HCl) is 0.2 M, you just need to find half of that concentration:

Half molarity = M / 2 = 0.2 M / 2 = 0.1 M

So, the answer is the first choice: a. 0.1 M.

3 0

3 years ago

Answer question number 2

kipiarov [429]

Answer:

it would be the second choice

3 0

3 years ago