If steel (a metal) is hard and granite (a nonmetal) is hard, why don’t we make automobile engines out of granite?

The burning of magnesium is a highly exothermic reaction. How many kilojoules of heat are released when 0. 75 mol of Mg burn in

alexandr402 [8]

Taking into account the definition of enthalpy of a chemical reaction, the quantity of heat released when 0.75 moles of Mg are burned is 451.5 kJ.

<h3>Enthalpy of a chemical reaction</h3>

The enthalpy of a chemical reaction is known as the heat absorbed or released in a chemical reaction when it occurs at constant pressure. That is, the heat of reaction is the energy that is released or absorbed when chemicals are transformed into a chemical reaction.

The enthalpy is an extensive property, that is, it depends on the amount of matter present.

<h3>Heat released in this case</h3>

In this case, the balanced reaction is:

2 Mg(s) + O₂ (g) → 2 MgO(s) + 1204 kJ

This equation indicates that when 2 moles of Mg reacts with 1 mole of O₂, 1204 kJ of heat is released.

When 0.75 moles of Mg are burned, then you can apply the following rule of three: if 2 moles of Mg releases 1204 kJ of heat, 0.75 moles of Mg releases how much heat?

$heat=\frac{0.75 moles of Mgx1204 kJ}{2 moles of Mg}$

Finally, the quantity of heat released when 0.75 moles of Mg are burned is 451.5 kJ.

Learn more about enthalpy of a chemical reaction:

<u>brainly.com/question/15355361</u>

<u>brainly.com/question/16982510</u>

<u>brainly.com/question/13813185</u>

<u>brainly.com/question/19521752</u>

4 0

2 years ago

Maggie has 4 binders with 30 stamps in each binder. She has 3 binders with 36 baseball cards in each binder. If she gives away 4

Sliva [168]

Answer:

The number of stamps and cards Maggie has left if she gives 45 stamps to a friend is 183

Explanation:

If Maggie gives 45 stamps to a friend, you must calculate the number of stamps and cards she has left.

You know Maggie has 4 folders with 30 stamps in each folder. So the number of stamps she owns is calculated as:

4 folders*30 stamps in each folder= 120 stamps

If Maggie gives 45 stamps to a friend, then the number of stamps she has left will be calculated as the difference (the subtraction) between the stamps she owned and the ones she gives away:

120 stamps - 45 stamps= 75 stamps

On the other hand, she has 3 binders with 36 baseball cards in each binder. So the number of cards she owns is calculated as:

3 binders * 36 baseball cards in each binders= 108 baseball cards

The number of stamps and cards you have left is calculated as:

75 stamps + 108 baseball cards= 183

<em><u>The number of stamps and cards Maggie has left if she gives 45 stamps to a friend is 183</u></em>

4 0

2 years ago

When 3.0 kg of water is warmed from 10 °C to 80 °C, how much heat energy is needed?

Naddik [55]

Answer:

THE HEAT NEEDED TO CHANGE 3KG OF WATER FROM 10 C TO 80 C IS 877.8kJ OR 877,800 J.

Explanation:

Mass = 3.0 kg = 3 * 1000 = 3000 g

Initial temperature = 10 C

Final temperature = 80 C

Change in temperature = 80 - 10 = 70 C

Specific heat of water = 4.18 J/g C

Heat needed = unknown

Heat is the amount of energy in joules needed to change a gram of water by 1 C.

Heat = mass * specific heat * change in temperature

Heat = 3000 g * 4.18 J/g C * 70 C

Heat = 877 800 Joules

Heat = 877.8 kJ.

The heat needed to change 3 kg mass of water from 10 C to 80 C is 877,800 J or 877.8 kJ.

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3 years ago

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WARRIOR [948]

Türkiye cumhuriyeti ccc

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What do you think are some of the most pressing environmental science issues

Nezavi [6.7K]

Answer:

i believe global warming

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