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3 years ago

What does heat mean in chemistry

Chemistry

1 answer:

Tpy6a [65]3 years ago

8 0

Answer:

Heat is the transfer of energy that results from the difference in temperature between a system and its surroundings. At a molecular level, heat is the transfer of energy that makes use of or stimulates disorderly molecular motion in the surroundings.

Explanation:

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Which of the following temperature scales contains an absolute zero? Fahrenheit (°F) Celsius (°C) Kelvin (K)

melamori03 [73]

Kelvin (K) is the only scale that has a numeral value assigned to absolute zero.

8 0

3 years ago

What is the difference between a pulley and incline plane?

erik [133]

A incline plane is a flat inclined surface. You can stick a rope in the pulley and pull one side and the other side will lift something! They are both simple machines! The difference is a incline plane is a ramp and things go up or down and the pulley lifts something with force of your weight!!

3 0

3 years ago

Read 2 more answers

This is hard, isn't it? please help me though. PLEASE

Liono4ka [1.6K]

I think it might be A. i am not totally sure though

6 0

2 years ago

in a simulation mercury removal from industrial wastewater, 0.020 L of 0.10 M sodium sulfide reacts with 0.050 L of 0.010 M merc

Margarita [4]

Answer: 0.1161 grams of mercury(II) sulfide) form.

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in L)}}$ .....(1)

a) Molarity of $Na_2S$ solution = 0.10 M

Volume of solution = 0.020 L

Putting values in equation 1, we get:

$0.10M=\frac{\text{Moles of }Na_2S}{0.020L}\\\\\text{Moles of Na_2S}={0.10mol/L\times 0.020}=0.002mol$

$\text {Moles of}Na_2S=0.10M\times 0.020L=0.002mol$

b) Molarity of $Hg(NO_3)_2$ solution = 0.010 M

Volume of solution = 0.050 L

Putting values in equation 1, we get:

$0.010M=\frac{\text{Moles of }Hg(NO_3)_2}{0.050L}\\\\\text{Moles of }Hg(NO_3)_2={0.010mol/L\times 0.050}=0.0005mol$

$Na_2S+Hg(NO_3)_2\rightarrow HgS+2NaNO_3$

According to stoichiometry :

1 mole of $Hg(NO_3)_2$ reacts with 1 mole of $Na_2S$

Thus 0.0005 moles of $HgNO_3$ reacts with= $\frac{1}{1}\times 0.0005=0.0005$ moles of $Hg(NO_3)_2$

Thus $Hg(NO_3)_2$ is the limiting reagent and $Na_2S$ is the excess reagent.

According to stoichiometry :

1 mole of $Hg(NO_3)_2$ forms= 1 mole of $Hg_2S$

Thus 0.0005 moles of $Hg(NO_3)_2$ forms= $\frac{1}{1}\times 0.0005=0.0005$ moles of $Hg_2S$

mass of $H_2S=moles\times {\text {Molar mass}}=0.0005mol\times 232.2g/mol=0.1161g$

Thus 0.1161 grams of mercury(II) sulfide) form.

5 0

3 years ago

The activation energy for a reaction is changed from 184 kJ/mol to 60.5 kJ/mol at 600. K by the introduction of a catalyst. If t

Ahat [919]

Answer:

The catalyzed reaction will take 1,41 s

Explanation:

The rate constant for a reaction is:

$k = A e^{-\frac{Ea}{RT}}$

Assuming frequency factor is the same for both reactions (with and without catalyst) it is possible to obtain:

${\frac{k1}{k2}} = e^{-\frac{Ea_{2}-Ea_{1}}{RT}}$

Replacing:

${\frac{k1}{k2}} = e^{-\frac{60,5kJ/mol-184kJ/mol}{8,314472x10^{-3}kJ/molK*600k}}$

${\frac{k1}{k2}} = 5,64x10^{10}$

That means the reaction occurs 5,64x10¹⁰ faster than the uncatalyzed reaction, that is 2537 years / 5,64x10¹⁰ = 4,50x10⁻⁸ years. In seconds:

4,50x10⁻⁸ years× $\frac{365days}{1year}$ × $\frac{24hours}{1day}$ × $\frac{3600s}{1hour}$ =<em> 1,41 s</em>

I hope it helps!

6 0

3 years ago