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Harlamova29_29 [7]

3 years ago

5

Why do heated molecules rise? a Because they are less dense than the molecules around them b Because they are moving slower than

the other molecules c Because they are denser than the molecules around them

1 answer:

Volgvan3 years ago

7 0

Answer:

A because they are less dense than the molecules around them

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Is phosphorous dissolving in carbon disulfide a physical or chemical property? if physical, is it intensive or extensive?

Nana76 [90]

Answer: Phosphorus is insoluble in water, but soluble in carbon disulfide. Phosphorus burns spontaneously in air to its pentoxide.

Explanation: Hope this helped! :)

3 0

3 years ago

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A box is sitting on a table. The upward force exerted on the box that stops it from falling through the table is known as the __

romanna [79]

It is know as the normal force.

When a solid is placed on a support, the latter exerts forces on the solid at each point of contact. These are forces that oppose the weight and prevent an object from falling.

This force is usually vertical and upward and often offsets the weight. If the solid is in equilibrium on the support the forces compensate the weight of the solid.

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3 years ago

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Calculate the total energy, in kilojoules, that is needed to turn a 46 g block

neonofarm [45]

Answer: The total energy, in kilojoules, that is needed to turn a 46 g block of ice at -25 degrees C into water vapor at 100 degrees C is 11.787 kJ.

Explanation:

Given: Mass = 46 g

Initial temperature = $-25^{o}C$

Final temperature = $100^{o}C$

Specific heat capacity of ice = 2.05 $J/g^{o}C$

Formula used to calculate the energy is as follows.

$q = m \times C \times (T_{2} - T_{1})$

where,

q = heat energy

m = mass

C = specific heat capacity

$T_{1}$ = initial temperature

$T_{2}$ = final temperature

Substitute the values into above formula as follows.

$q = m \times C \times (T_{2} - T_{1})\\= 46 g \times 2.05 J/g^{o}C \times (100 - (-25))^{o}C\\= 11787.5 J (1 J = 0.001 kJ)\\= 11.787 kJ$

Thus, we can conclude that the total energy, in kilojoules, that is needed to turn a 46 g block of ice at -25 degrees C into water vapor at 100 degrees C is 11.787 kJ.

7 0

3 years ago

Consider the reaction:

murzikaleks [220]

<u>Answer:</u> The formation of given amount of oxygen gas results in the absorption of 713 kJ of heat.

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of oxygen gas = 83 g

Molar mass of oxygen gas = 32 g/mol

Putting values in above equation, we get:

$\text{Moles of oxygen gas}=\frac{83g}{32g/mol}=2.594mol$

For the given chemical equation:

$2Fe_2O_3\rightarrow 4Fe+3O_2;\Delta H^o_{rxn}=+824.2kJ$

<u>Sign convention of heat:</u>

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

By Stoichiometry of the reaction:

When 3 moles of oxygen gas is formed, the amount of heat absorbed is 824.2 kJ

So, when 2.594 moles of oxygen gas is formed, the amount of heat absorbed will be = $\frac{824.2kJ}{3mol}\times 2.59mol=713kJ$

Hence, the formation of given amount of oxygen gas results in the absorption of 713 kJ of heat.

7 0

4 years ago

Propose structures that meet the following descriptions. Use bond-line notation to draw your structural formulas. a. ketone with

bija089 [108]

Answer:

See explanation

Explanation:

In putting up prospective structures for the compounds, we must consider the tetra valency of carbon. Again you must read the description carefully before drawing each structure.

In each of the proposed structures, the number of atoms present must reflect the condensed structural formula given in the question.

Proposed structures for each chemical specie in the question are shown in the images attached.

7 0

4 years ago