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3 years ago

A student uses a lever and fulcrum to lift a rock off the ground.

Chemistry

2 answers:

chubhunter [2.5K]3 years ago

8 0

I think it’s b hope this helps

Sedaia [141]3 years ago

7 0

it has to me b because it shows what they did in this part

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the student records the concentration of the stock solution of H2O2 to be 0.950 M. The student proceeds to prepare the reaction

lana [24]

Answer:

0.0400M of KI

Explanation:

Molarity is an unit of concentration defined as the ratio between moles of solute and liters of solution.

When you add 10.0 mL of 0.10M KI and 15.0mL, total volume is:

25.0mL = 0.025L of solution

And moles of KI are:

0.0100L × 0.10M = 0.00100 moles of KI

Thus, molarity is:

0.00100 moles / 0.025L = 0.0400M of KI

6 0

3 years ago

What did you include in your response? check all that apply

erma4kov [3.2K]

Answer: i don't know

Explanation:

u gave no information on what you're asking

6 0

3 years ago

The activation energy for a reaction is changed from 184 kJ/mol to 59.0 kJ/mol at 600. K by the introduction of a catalyst. If t

11111nata11111 [884]

Answer:

The catalyzed reaction will take 2.85 seconds to occur.

Explanation:

The activation energy of a reaction is given by:

$k = Ae^{-\frac{E_{a}}{RT}}$

For the reaction without catalyst we have:

$k_{1} = Ae^{-\frac{E_{a_{1}}}{RT}}$ (1)

And for the reaction with the catalyst:

$k_{2} = Ae^{-\frac{E_{a_{2}}}{RT}}$ (2)

Assuming that frequency factor (A) and the temperature (T) are constant, by dividing equation (1) with equation (2) we have:

$\frac{k_{1}}{k_{2}} = \frac{Ae^{-\frac{E_{a_{1}}}{RT}}}{Ae^{-\frac{E_{a_{2}}}{RT}}}$

$\frac{k_{1}}{k_{2}} = e^{\frac{E_{a_{2}} - E_{a_{1}}}{RT}$

$\frac{k_{1}}{k_{2}} = e^{\frac{59.0 \cdot 10^{3}J/mol - 184 \cdot 10^{3} J/mol}{8.314 J/Kmol*600 K} = 1.31 \cdot 10^{-11}$

Since the reaction rate is related to the time as follow:

$k = \frac{\Delta [R]}{t}$

And assuming that the initial concentrations ([R]) are the same, we have:

$\frac{k_{1}}{k_{2}} = \frac{\Delta [R]/t_{1}}{\Delta [R]/t_{2}}$

$\frac{k_{1}}{k_{2}} = \frac{t_{2}}{t_{1}}$

$t_{2} = t_{1}\frac{k_{1}}{k_{2}} = 6900 y*1.31 \cdot 10^{-11} = 9.04 \cdot 10^{-8} y*\frac{365 d}{1 y}*\frac{24 h}{1 d}*\frac{3600 s}{1 h} = 2.85 s$

Therefore, the catalyzed reaction will take 2.85 seconds to occur.

I hope it helps you!

4 0

3 years ago

A introduction paragraph about coal and natural gas

lesantik [10]

Answer:

here is ur and

Explanation:

Coal, oil and natural gas are called fossil fuels. Fossil fuels are burned to make energy. Burning fossil fuels also releases CO2 (carbon dioxide) gas into the atmosphere. Most air pollutants (such as sulfur dioxide) don't stay in the atmosphere very long.

pls mark.me as brainliest

4 0

2 years ago

• identify early ideas about evolution

Andreyy89

There is two ideas about evolution.

1.) Religious
2.) Scientific

In the religious one, people believe that we were created through god.

In the scientific one, people believe that we were created from apes and that throughout time we became humans.

7 0

3 years ago