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Rzqust [24]
3 years ago
11

How much heat is released as the temperature of 25.2 grams of iron is decreased from 72.1°C to 9.8°C? The specific heat of iron

is 0.444 J/g·°C.
Chemistry
1 answer:
prisoha [69]3 years ago
8 0

Answer:

Q=-697.06\ J

Negative sign says that release of heat.

Explanation:

The expression for the calculation of the heat released or absorbed of a process is shown below as:-

Q=m\times C\times \Delta T

Where,  

\Delta H  is the heat released or absorbed

m is the mass

C is the specific heat capacity

\Delta T  is the temperature change

Thus, given that:-

Mass = 25.2 g

Specific heat = 0.444 J/g°C

\Delta T=9.8-72.1\ ^0C=-62.3\ ^0C

So,  

Q=25.2\times 0.444\times -62.3\ J=-697.06\ J

Negative sign says that release of heat.

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Which reaction is used to produce polyethylene from ethylene
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  Addition polymerization
         .....Hope it helps, Have a good rest of the day:)
5 0
3 years ago
When the pressure that a gas exerts on a sealed container changes from 893 mm hg to 778 mm hg, the temperature changes from 49.3
solong [7]

Answer: The final temperature of the gas is 7.58 °C.

Explanation: We are given initial and final pressure of the system and we need to find the final temperature of the system.

To calculate it, we use the equation given by Gay-Lussac.

His law states that pressure is directly related to the temperature of the gas.

P\propto T

Or,

\frac{P_1}{T_1}=\frac{P_2}{T_2}

where,

P_1 = initial pressure = 893 mmHg = 1.175atm (Conversion factor: 1atm = 760mmHg)

T_1 = initial temperature = 49.3°C = [49.3 + 273.15]K = 322.45K

P_2 = Final pressure = 778mmHg = 1.023atm

T_ = Final temperature = ?°C

Putting values in above equation, we get:

\frac{1.175atm}{322.45K}=\frac{1.023atm}{T_2}\\\\T_2=280.73K

Converting Final temperature from kelvin to degree Celsius.

T_2=280.73K=[280.73-273.15]^oC=7.58^oC

Hence, the final temperature of the gas is 7.58 °C.

5 0
3 years ago
Read 2 more answers
At 25 oC, hydrogen iodide breaks down very slowly to hydrogen gas and iodine vapor with a rate constant of 2.4 x 10-21L/mol.s. I
Ratling [72]

Answer:

\large \boxed{4.6 \times 10^{21}\text{ s}}

Explanation:

Whenever a question asks you, "What is the concentration after a given time?" or something like that, you must use the appropriate integrated rate law expression.

The reaction is 2nd order, because the units of k are L·mol⁻¹s⁻¹.

The integrated rate law for a second-order reaction is  

\dfrac{1}{\text{[A]}} =\dfrac{1}{\text{[A]}_{0}}+ kt

Data:

   k = 2.4 × 10⁻²¹ L·mol⁻¹s⁻¹

[A]₀ = 0.0100     mol·L⁻¹

[A] = 0.009 00 mol·L⁻¹

Calculation :

\begin{array}{rcl}\dfrac{1}{\text{[A]}} & = & \dfrac{1}{\text{[A]}_{0}}+ kt\\\\\dfrac{1}{0.00900 }& = & \dfrac{1}{0.0100} + 2.4 \times 10^{-21} \, t\\\\111.1&=& 100.0 + 2.4 \times 10^{-21} \, t\\\\11.1& = & 2.4 \times 10^{-21} \, t\\t & = & \dfrac{11.1}{ 2.4 \times 10^{-21}}\\\\& = & \mathbf{4.6 \times 10^{21}}\textbf{ s}\\\end{array}\\\text{It will take $\large \boxed{\mathbf{4.6 \times 10^{21}}\textbf{ s}}$ for the HI to decompose}

8 0
3 years ago
Mole ratios how can the coefficients in a chemical equation be interpreted
navik [9.2K]

Answer:

The coefficient in a balanced chemical equation  indicates the mole ratio of both reactants and products.  

Explanation:

For example lets consider the reation between Hydrogen and Oxygen to form water:

2H2 + O2 ----------------------- 2H2O

In this reaction, the coefficients of the balanced reaction can be transformed to Mole ratio according to Avogadro's Law which states that at standard temperature and pressure, equal volume of gases contain the same  number of moles.

So the mole ratio for the above equation is  the  ratio of the coefficient:

2moles     :     1 mole               :          2 moles

8 0
3 years ago
9, What is an Independent
stepan [7]

Answer:

Not influenced or controlled by others in matters of opinion

8 0
3 years ago
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