Please help me it's just one question!

a sample of cobalt (specific heat of Co=0.418J/G C )at 100.0 C is dropped into a calorimeter containing 500.0 mL of water at 21.

Alex17521 [72]

Answer:

$m_{Co}=6998g=7.0kg$

Explanation:

Hello there!

In this case, according to this equilibrium temperature problem, we can set up the following equation to relate the mass, specific heat and temperature change:

$Q_{Co}=-Q_{w}\\\\m_{Co}C_{Co}(T_f-T_{Co})=-m_{w}C_{w}(T_f-T_{w})$

Thus, we solve for the mass of cobalt as shown below:

$m_{Co}=\frac{-m_{w}C_{w}(T_f-T_{w})}{C_{Co}(T_f-T_{Co})} \\\\m_{Co}=\frac{-500.00g*4.184J/g\°C(67.1\°C-21.1\°C)}{0.418J/g\°C(67.1\°C-100\°C)} \\\\m_{Co}=6998g=7.0kg$

Best regards!

7 0

3 years ago

A glass laboratory flask is filled with gas at 24 ∘C and 0.95 atm pressure, sealed, and then heated to 104 ∘C. What is the press

Elan Coil [88]

The pressure inside the flask on heating it is given as 1.21 atm.

<u>Explanation:</u>

As per Guy Lussac's law, the pressure of any concealed volume of gas particles will be directly proportional to the temperature of the container of the gas particles.

So P ∝ T

To convert celsius to kelvin, add 273.15 to the temperature value in celsius

Since, here the initial temperature of the flask is given as 24°C, so in kelvin it will be 297.15 K. Similarly, the final temperature is said to be 104°C which will be equal to 377.15 K. Then the final pressure will be increased as there is increase in temperature. So, the final pressure inside the flask can be obtained as

$\frac{P_{1} }{T_{1} } = \frac{P_{2} }{T_{2} }$

$P_{2} = \frac{P_{1} }{T_{1} } \times T_{2} =\frac{0.95}{297.15} \times 377.15 =1.21\ atm$

So, the pressure inside the flask on heating it is given as 1.21 atm.

3 0

4 years ago

A fat is composed of long chains of carbon and hydrogen atoms. In a reaction with a strong base, a fat forms a soap and glycerol

Nonamiya [84]

Answer:

Empirical formula is C₉H₁₅O

Molecular formula = C₈₁H₁₃₅O ₉

Explanation:

Percentage of carbon = 77.60%

Percentage of oxygen = 11.45%

Percentage of hydrogen = 10.95%

Molecular weight = 1253 g/mol

Molecular formula = ?

Empirical formula = ?

Solution:

Number of gram atoms of C = 77.60 g /12g/mol =6.5

Number of gram atoms of O = 11.45 g / 16 g/mol = 0.72

Number of gram atoms of H = 10.95 g / 1.008 g/mol= 10.9

Atomic ratio:

C : H : O

6.5/0.72 : 10.9/0.72 : 0.72/0.72

9 : 15 : 1

C : H : O = 9 : 15 : 1

Empirical formula is C₉H₁₅O

Molecular formula:

Molecular formula = n (empirical formula)

n = molar mass of compound / empirical formula mass

n = 1253 / 139

n = 9

Molecular formula = n (empirical formula)

Molecular formula = 9 (C₉H₁₅O )

Molecular formula = C₈₁H₁₃₅O ₉

4 0

4 years ago

jenny dissolves as much salt as she can in 100mL of room temperature water. she learned in class that less salt will dissolve in

Slav-nsk [51]

Answer:

if ice is added more salt can be dissolved ...........

5 0

3 years ago

Read 2 more answers

What is the pH of a solution with a [H+] = 1.0 x 10-5

PIT_PIT [208]

Answer:

Explanation:

The pH of a solution can be found by using the formula

$pH = - log ([ {H}^{+} ])$

From the question we have

$pH = - log(1.0 \times {10}^{ - 5} ) \\ = 5$

We have the final answer as

Hope this helps you

7 0

3 years ago