The mass number of an atom is equal to which of the following?

Solution X is a strong base with a pH of 12. Solution X is mixed with solution Y,and the pH of the resulting mixture is 8.Based

myrzilka [38]

The strong Base with a pH of 12 is reduced by 4 units upon being added with solution Y. If you added a strong acid to the strong base, all ions are present in the solution, yes? So every OH- is neutralised by every H+ for example, meaning the resultant pH should be 7. The resultant pH is only 8 however, so solution Y must be a weak acid only!

5 0

2 years ago

Choose ALL TRUE statements about calorimetry from the choices below:

Ostrovityanka [42]

Answer:

True statment

2) Styrofoam would make a good calorimeter

3) Insulating material would make a good calorimeter

Explanation:

The calorimeter is one which is insulated that is which will not absorb or let the heat to escape from it. the calorimeter is used to measure the heat change during a process so if it will allow to exchange heat with surrounding it will deviate the readings or observence.

Copper is a good conductor of heat so we cannot use it make a calorimeter.

Hence

1) Copper would make a good calorimeter : False

2) Styrofoam would make a good calorimeter: True

Styrofoam is a bad conductor or insulator so it can be and it is used for calorimeter.

3) Insulating material would make a good calorimeter : True

4) A good calorimeter should easily absorb heat : false

6 0

2 years ago

Use one of your experimentally determined values of k, the activation energy you determined, and the Arrhenius equation to calcu

stealth61 [152]

Answer:

Explanation:

Use one of your experimentally determined values of k, the activation energy you determined, and the Arrhenius equation to calculate the value of the rate constant at 25 °C. Alternatively, you can simply extrapolate the straight line plot of ln(k) vs. 1/T in your notebook to 1/298 , read off the value of ln(k), and determine the value of k. Please put your answer in scientific notation. slope=-12070, Ea=100kJ/mol, k= 0.000717(45C), 0.00284(55C), 0.00492(65C), 0.0165(75C), 0.0396(85C)

Explanation;

According to Arrhenius equation:

i.e. ln(k2/k1) = -Ea/R (1/T2 - 1/T1)

Where, k1 = 0.000717, T1 = 45 oC = (45+273) K = 318 K

T2 = 25 oC = (25 + 273) K = 298 K

i.e. ln(k2/0.000717) = -12070 (1/298 - 1/318)

i.e. ln(k2/0.000717) = -2.54738

i.e. k2/0.000717 = $e^{-2.54738}$

= 0.078286

Therefore, the required constant (k2) = 0.078286 * 0.000717 = $5.61*10^-^5$

6 0

2 years ago

54.56 g of water at 80.4 oC is added to a calorimeter that contains 47.24 g of water at 40 oC. If the final temperature of the s

fomenos

Answer:

49.5J/°C

Explanation:

The hot water lost some energy that is gained for cold water and the calorimeter.

The equation is:

Q(Hot water) = Q(Cold water) + Q(Calorimeter)

Where:

Q(Hot water) = S*m*ΔT = 4.184J/g°C*54.56g*(80.4°C-59.4°C) = 4794J

Q(Cold water) = S*m*ΔT = 4.184J/g°C*47.24g*(59.4°C-40°C) = 3834J

That means the heat gained by the calorimeter is

Q(Calorimeter) = 4794J - 3834J = 960J

The calorimeter constant is the heat gained per °C. The change in temperature of the calorimeter is:

59.4°C-40°C = 19.4°C

And calorimeter constant is:

960J/19.4°C =

7 0

2 years ago

Given equilibrium partial pressures of PNO2= 0.247 atm, PNO = 0.0022atm, and PO2 = 0.0011 atm calculate the equilibrium constant

maxonik [38]

Answer 1:
Equilibrium constant (K) mathematically expressed as the ratio of the concentration of products to concentration of reactant. In case of gaseous system, partial pressure is used, instead to concentration.

In present case, following reaction is involved:

2NO2 ↔ 2NO + O2

Here, K = $\frac{[PNO]^2[O2]}{[PNO2]^2}$

Given: At equilibrium, PNO2= 0.247 atm, PNO = 0.0022atm, and PO2 = 0.0011 atm

Hence, K = $\frac{[0.0022]^2[0.0011]}{[0.247]^2}$
= 8.727 X 10^-8

Thus, equilibrium constant of reaction = 8.727 X 10^-8
.......................................................................................................................

Answer 2:
Given: PNO2= 0.192 atm, PNO = 0.021 atm, and PO2 = 0.037 atm.

Therefore, Reaction quotient = $\frac{[PNO]^2[O2]}{[PNO2]^2}$
= $\frac{[0.021]^2[0.037]}{[0.192]^2}$
= 4.426 X 10^-4.

Here, Reaction quotient > Equilibrium constant.

Hence, the reaction need to go to reverse direction to reattain equilibrium

5 0

2 years ago

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