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3 years ago

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1 answer:

6 0

4. density, temperature, surface tension.
7. extensive properties- uses mass and volume depends on tbe amount of substance present.

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Calculate the pH of the following simple solutions:

IceJOKER [234]

Answer :

(1) pH = 1.27

(2) pH = 13.35

(3) The given solution is not a buffer.

Explanation :

(1) 53.1 mM HCl

Concentration of HCl = $53.1mM=53.1\times 10^{-3}M$

As HCl is a strong acid. So, it dissociates completely to give hydrogen ion and chloride ion.

So, Concentration of hydrogen ion= $53.1\times 10^{-3}M$

pH : It is defined as the negative logarithm of hydrogen ion concentration.

$pH=-\log [H^+]$

$pH=-\log (53.1\times 10^{-3})$

$pH=1.27$

(2) 0.223 M KOH

Concentration of KOH = 0.223 M

As KOH is a strong base. So, it dissociates completely to give hydroxide ion and potassium ion.

So, Concentration of hydroxide ion= 0.223 M

Now we have to calculate the pOH.

$pOH=-\log [OH^-]$

$pOH=-\log (0.223)$

$pOH=0.65$

Now we have to calculate the pH.

$pH+pOH=14\\\\pH=14-pOH\\\\pH=14-0.65=13.35$

(3) 53.1 mM HCl + 0.223 M KOH

Buffer : It is defined as a solution that maintain the pH of the solution by adding the small amount of acid or a base.

It is not a buffer because HCl is a strong acid and KOH is a strong base. Both dissociates completely.

As we know that the pH of strong acid and strong base solution is always 7.

So, the given solution is not a buffer.

5 0

3 years ago

According to the rate law, how do concentrations affect rate?

IrinaK [193]

D, the rate increases as concentrations increase.

Typically, reaction rates decrease with time because reactant concentrations decrease as reactions are converted to products. Reaction rates generally increase when reactant concentrations are increased.

6 0

3 years ago

Read 2 more answers

The heat of reaction for the combustion of propane is –2,045 kJ. This reaction is: C3H8(g) +502 (g) 3CO2 (g) + 4H2O (g). Determi

Ede4ka [16]

Answer:

$\Delta _fH_{C_3H_8}=-102.7kJ/mol$

Explanation:

Hello,

In this case, we can consider that the given heat of combustion is indeed the heat of reaction since it corresponds to the combustion of propane, which is computed by using the heat formation of all the involved species as shown below:

$\Delta _cH=3*\Delta _fH_{CO_2}+4*\Delta _fH_{H_2O}-\Delta _fH_{C_3H_8}-5*\Delta _fH_{O_2}$

Thus, since the heat of formation of gaseous carbon dioxide is -393.5 kJ/mol, water -241.8 kJ/mol and oxygen 0 kJ/mol, the heat of formation of propane is:

$\Delta _fH_{C_3H_8}=3*\Delta _fH_{CO_2}+4*\Delta _fH_{H_2O}-5*\Delta _fH_{O_2}-\Delta _cH\\\\\Delta _fH_{C_3H_8}=3*(-393.5)+4*(-241.8)-5*0-(-2045)\\\\\Delta _fH_{C_3H_8}=-102.7kJ/mol$

Best regards.

8 0

3 years ago

Object A specific heat is 2.45 J/g C and object B specific heat is 0.82 J/g C. Which object will heat up more if they have the s

Artist 52 [7]

Answer: Object B will heat up more.

Explanation:

The formula for specific heat is as follows.

Q = $m C \Delta T$

Where,

Q = heat provided

m = mass

C = specific heat

$\Delta T$ = change in temperature

Now, both the objects have same mass and equal amount of heat is applied.

According to the formula, the equation will be as follows.

$Q_{1}$ = $Q_{2}$

$m C_{1}\Delta T$ = $m C_{2}\Delta T_{2}$

Cancel m from both sides, as mass is same. Therefore,

$C_{1} (T_{f} - T_{i})_A$ = $C_{2}(T_{f} - T_{i})_B$

Cancel out the initial temperature and put the values of specific heat, then the equation will be as follows.

$2.45 (T_{f})_A$ = $0.82(T_{f})_B$

Therefore, from the above equation it can be concluded that the object with low specific heat will heat up more as its specific heat will be inversely proportional to its final temperature.

Hence, object B will heat up more.

4 0

3 years ago

40 points

amm1812

Answer:

I am so confused about this i am so sorry but i cant there is to much going on

Explanation:

7 0

3 years ago

Read 2 more answers