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3 years ago

74. Which two temperatures are identical for the same substance?

Chemistry

1 answer:

AURORKA [14]3 years ago

4 0

Answer:

(A) melting point, freezing point.

Explanation:

For the same substance: when matter is transitioning from solid to liquid (melting) or liquid to solid (freezing), its temperature is fixed at the melting/freezing point, which is the same temperature.

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Which of the following reactions involves a single compound producing two or more simpler substances?

castortr0y [4]

Answer:

Decomposition or cracking

Explanation:

In a decomposition or cracking reaction, a single compound produces two or more simpler substances.

It involves the formation of two or more products from a single reactant.

A → B + C

A is the single reactant

B and C are the products

The driving force for such a reaction is the is high positive heat of formation of the compound that is, extreme instability of the compound.

6 0

3 years ago

How many molecules are there in 8.25 moles of CaHia?

expeople1 [14]

The number of molecules : 4.967 x 10²⁴

<h3>Further explanation </h3>

A mole is a number of particles(atoms, molecules, ions) in a substance

This refers to the atomic total of the 12 gr C-12 which is equal to 6.02.10²³, so 1 mole = 6.02.10²³ particles

Can be formulated :

N = n x No

N = number of particles

n = mol

No = 6.02.10²³ = Avogadro's number

8.25 moles of C₈H₁₈

The number of molecules :

$\tt 8.25\times 6.02\times 10^{23}=4.967\times 10^{24}$

8 0

3 years ago

Which of the following (with specific heat capacity provided) would show the smallest temperature change upon gaining 200.0 J of

Brut [27]

Answer: The smallest temperature change is shown by water.

Explanation:

To calculate the heat absorbed or released, we use the equation:

$q=mC\times \Delta T$ ......(1)

where,

q = heat absorbed = 200.0 J

m = mass of the substance

C = specific heat of substance

$\Delta T$ = change in temperature

As, the same amount of heat is getting absorbed in all the cases. So, the change in temperature will depend on the product of mass and specific heat.

For the given options:

Option a: 50.0 g Fe, $C_{Fe}=0.449J/g^oC$

We are given:

$m=50.0g\\C_{Fe}=0.449J/g^oC$

Putting values in equation 1, we get:

$200.0J=50.0g\times 0.449J/g^oC\times \Delta T\\\\\Delta T=\frac{200}{50\times 0.449}=8.99^oC$

Change in temperature = 8.99°C

Option b: 50.0 g water, $C_{water}=4.18J/g^oC$

We are given:

$m=50.0g\\C_{water}=4.18J/g^oC$

Putting values in equation 1, we get:

$200.0J=50.0g\times 4.18J/g^oC\times \Delta T\\\\\Delta T=\frac{200}{50\times 4.18}=0.96^oC$

Change in temperature = 0.96°C

Option b: 25.0 g Pb, $C_{Pb}=0.128J/g^oC$

We are given:

$m=50.0g\\C_{Pb}=0.128J/g^oC$

Putting values in equation 1, we get:

$200.0J=25.0g\times 0.128J/g^oC\times \Delta T\\\\\Delta T=\frac{200}{25\times 0.128}=62.5^oC$

Change in temperature = 62.5°C

Option d: 25.0 g Ag, $C_{Ag}=0.235J/g^oC$

We are given:

$m=25.0g\\C_{Ag}=0.235J/g^oC$

Putting values in equation 1, we get:

$200.0J=25.0g\times 0.235J/g^oC\times \Delta T\\\\\Delta T=\frac{200}{25\times 0.235}=34.04^oC$

Change in temperature = 34.04°C

Option e: 25.0 g granite, $C_{granite}=0.79J/g^oC$

We are given:

$m=25.0g\\C_{Fe}=0.79J/g^oC$

Putting values in equation 1, we get:

$200.0J=25.0g\times 0.79J/g^oC\times \Delta T\\\\\Delta T=\frac{200}{25\times 0.79}=10.13^oC$

Change in temperature = 10.13°C

Hence, the smallest temperature change is shown by water.

5 0

3 years ago

Bromine is is reddish-brown liquid that boils at 59 degrees. bromine is highly reactive with many metals, for example, it reacts

katrin2010 [14]

A physical property of an element is a property of an element that can observed or measured without changing the chemical nature of the element.

A chemical property of an element is a property of an element that can only be observed or measure when the chemical property of the element is altered or changed.

Based on this;
The boiling point of bromine is a physical property of bromine.
The high reactivity of bromine with many elements is a chemical property of bromine.

4 0

3 years ago

Two hydraulic cylinders are connected. If the diameter of one piston is twice the other, the how does the pressure experienced b

Aneli [31]

Answer:

They experience the same pressure

Explanation:

To answer this question, we recall Pascal's, Law Pascal's law states that an increase in pressure at a point in a confined cylinder containing a fluid, there is also an equal increase at all other points in that cylinder.

According to Pascal's law the pressure if the pressure expereienced by the larger diameter piston increases, the pressure experienced by the smaller diameter piston also increases by the same amount

However considering that pressure = Force/area F1/A1 =F2/A2

thus where A1 = πD²÷4 and A2 = πD²÷ 16 we have

we have F1×4/πD² = F2×16/πD² or F1 = 4× F2

They experience the same pressure but the larger cylinder delivers four times the force transmitted from he outside to the smaller cylinder

7 0

3 years ago