Which group of elements ,in the periodic table, would most likely be used for electrical wires?

How does a catalyst speed up a chemical reaction

ser-zykov [4K]

By being an alternative route to the reaction with a lower activation energy.

5 0

3 years ago

Read 2 more answers

HELP PLEASE I HAVE A TEST TODAY AND I DON'T UNDERSTAND ANY OF THIS...

myrzilka [38]

Answer:

About 67 grams or 67.39 grams

Explanation:

First you would have to remember a few things:

enthalpy to melt ice is called enthalpy of fusion. this value is 6.02kJ/mol

of ice

it takes 4.18 joules to raise 1 gram of liquid water 1 degree C

water boils at 100 degrees C and water melts above 0 degrees C

1 kilojoules is 1000 joules

water's enthalpy of vaporization (steam) is 40.68 kJ/mol

a mole of water is 18.02 grams

we also have to assume the ice is at 0 degrees C

Step 1

Now start with your ice. The enthalpy of fusion for ice is calculated with this formula:

q = n x ΔH q= energy, n = moles of water, ΔH=enthalpy of fusion

Calculate how many moles of ice you have:

150g x (1 mol / 18.02 g) = 8.32 moles

Put that into the equation:

q = 8.32 mol x 6.02 = 50.09 kJ of energy to melt 150g of ice

Step 2

To raise 1 gram of water to the boiling point, it would take 4.18 joules times 100 (degrees C) or 418 joules.

So if it takes 418 joules for just 1 gram of water, it would take 150 times that amount to raise 150g to 100 degrees C. 418 x 150 = 62,700 joules or 62.7 kilojoules.

So far you have already used 50.09 kJ to melt the ice and another 62.7 kJ to bring the water to boiling. That's a total of 112.79 kJ.

Step 3

The final step is to see how much energy is left to vaporize the water.

Subtract the energy you used so far from what you were told you have.

265 kJ - 112.79 kJ = 152.21 kJ

Again q = mol x ΔH (vaporization)

You know you only have 152.21 kJ left so find out how many moles that will vaporize.

152.21 kJ = mol x 40.68 or mol = 152.21 / 40.68 = 3.74 moles

This tells you that you have vaporized 3.74 moles with the energy you have left.

Convert that back to grams.

3.74 mol x ( 18.02 g / 1 mol ) = 67.39 grams

5 0

2 years ago

Cuando se quema 1 mol de metano –o sea, 16 g–, se desprenden 802

Anvisha [2.4K]

Answer:

1 gramo de metano aporta 50.125 kilojoules.

1 gramo de metano aporta 48.246 kilojoules.

Explanation:

La cantidad de energía liberada por la combustión de una unidad de masa del hidrocarburo ( $Q$ ), en kilojoules por mol, es igual a la cantidad de energía liberada por mol de compuesto ( $\bar {Q}$ ), en kilojoules por mol, dividido por su masa molar ( $M$ ), en gramos por mol:

$Q = \frac{\bar Q}{M}$ (1)

A continuación, analizamos cada caso:

Metano

$Q = \frac{802\,\frac{kJ}{mol} }{16\,\frac{g}{mol} }$

$Q = 50.125\,\frac{kJ}{g}$

1 gramo de metano aporta 50.125 kilojoules.

Octano

$Q = \frac{5500\,\frac{kJ}{mol} }{114\,\frac{g}{mol} }$

$Q = 48.246\,\frac{kJ}{mol}$

1 gramo de metano aporta 48.246 kilojoules.

3 0

2 years ago

18. Use the activity series to predict whether the following synthesis reaction will occur. Write the chemical equations for the

MAXImum [283]

<u>Answer:</u> The chemical reaction for the synthesis reaction is given below.

<u>Explanation:</u>

Synthesis reaction is defined as a chemical reaction in which two small chemical substances combine together to form a single compound. The general equation for this chemical reaction follows:

$A+B\rightarrow AB$