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4 years ago

Why does hot water freeze faster than cold water?

2 answers:

8 0

warm water evaporates rapidly and since this is an endothermic process, it cools the water making it freeze more quickly.

weeeeeb [17]4 years ago

7 0

<h2>Answer:</h2>

<u>Temperature dependency is responsible for the process that hot water freeze faster than cold water.</u>

<h2>Explanation:</h2>

The effect given above is called Mpemba Effect. According to this idea hot water freezes more quickly as compared to cold water. But until now there is no convincing explanation for this strange phenomenon. One idea is that hot containers make better thermal contact with a refrigerator and so conduct heat more efficiently because a good conductor is good fro the transfer of heat. Another idea about this effect is that warm water evaporates more quickly and since this is an endothermic process, it cools the water making it freeze more quickly.

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Help plz:)))I’ll mark u Brainliest

emmasim [6.3K]

Answer:

$\Delta _{fus}H=205J/g=13.03kJ/mol$

Explanation:

Hello there!

In this case, since the heat of fusion is a property that allows us to calculate the heat involved during the change from solid to liquid (fusion) and is calculated as shown below:

$Q=m*\Delta _{fus}H$

In such a way, given the heat involved during this process and the mass of copper, we calculate the heat of fusion as shown below:

$\Delta _{fus}H=\frac{Q}{m}=\frac{41000J}{200.g}\\\\\Delta _{fus}H=205J/g$

Or in kJ/mol:

$\Delta _{fus}H=205\frac{J}{gCu}*\frac{63.546 gCu}{1molCu}\\\\ \Delta _{fus}H=13026.93J/mol=13.03kJ/mol$

Regards!

8 0

3 years ago

a compound contains 32 grams of O for every 2.0 grams of H. What is the most likely molecular formula of this compound?

Vedmedyk [2.9K]

Answer:

H₂O₂

Explanation:

The molecular formula gives the exact number of atoms within a chemical compound.

In this problem:

Mass of O = 32g

Mass of H = 2g

Let us follow this methodical approach to solve the problem:

Elements O H

Mass 32 2

Molar mass 16 1

Number of moles 32/16 2/1

2 2

The molecular formula of the compound is H₂O₂

4 0

3 years ago

The most abundant elements in the universe are hydrogen and helium, but there are also small but significant amounts of heavier

Stells [14]

Answer:

in nuclear fusion deep in the interiors of stars

Explanation:

Nuclear fusion -

It is the type of reaction , where two or more atomic nuclei of the atom merges together to release two or more different nuclei along with some subatomic particles , is referred to as a nuclear fusion reaction .

The reaction can very well be done on stars , because of very high energy .

Hence , a nuclear fusion occurs deep inside the stars .

7 0

3 years ago

Pure iron, Fe , can be produced from an ore called hematite, Fe2O3 , by reaction with carbon at high temperatures. 2Fe2O3+3C⟶4Fe

Sophie [7]

70 tons of hematite (Fe₂O₃) is needed to produce 49 tons of iron (Fe).

We'll begin by calculating the tons of hematite (Fe₂O₃) that reacted and the tons of Fe produced from the balanced equation. This is illustrated below:

2Fe₂O₃ + 3C —> 4Fe + 3CO₂

Molar mass of Fe₂O₃ = (56×2) + (16×3) = 160 g/mol

Mass of Fe₂O₃ from the balanced equation = 2 × 160 = 320 g

Divide by 907185 to express in ton

320 / 907185 = 0.000353 ton

Molar mass of Fe = 56 g/mol

Mass of Fe from the balanced equation = 56 × 4 = 224 g

Divide by 907185 to express in ton

224 / 907185 = 0.000247 ton

<h3>SUMMARY </h3>

From the balanced equation above,

0.000353 ton of Fe₂O₃ reacted to produce 0.000247 ton of Fe.

Finally, we shall determine the tons of hematite (Fe₂O₃) needed to produce 49 tons of Fe. This can be obtained as follow:

From the balanced equation above,

0.000353 ton of Fe₂O₃ reacted to produce 0.000247 ton of Fe.

Therefore,

X ton of Fe₂O₃ will react to produce 49 tons of Fe i.e

X ton of Fe₂O₃ = $\frac{0.000353 * 49}{0.000247} \\\\$

X ton of Fe₂O₃ = 70 tons

Thus, 70 tons of hematite (Fe₂O₃) is needed to produce 49 tons of Fe.

Learn more: brainly.com/question/15343472

5 0

3 years ago

When a calorimeter is used, no heat is exchanged between the contents of the container and the outside air. If an endothermic re

Kazeer [188]

<span>The total energy inside calorimeter will increase.</span>

5 0

3 years ago

Read 2 more answers