Answer:
2.8
Explanation:
First, we will calculate the molarity of the acetylsalicylic acid solution.
M = mass of solute (g) / molar mass of solute × volume of solution (L)
M = 0.327 g / 180.158 g/mol × 0.237 L
M = 7.66 × 10⁻³ M
For a weak acid such as acetylsalicylic acid, we can find the concentration of H⁺ using the following expression.
[H⁺] = √(Ca × Ka)
where,
Ca: concentration of the acid
Ka: acid dissociation constant
[H⁺] = √(7.66 × 10⁻³ × 3.3 × 10⁻⁴)
[H⁺] = 1.6 × 10⁻³ M
The pH is:
pH = -log [H⁺]
pH = -log 1.6 × 10⁻³ = 2.8
Answer:
are calculated by multiplying useful energy by the total amount of energy
Explanation:
The energy conversions are never 100 percent efficient. This is because the energy originally is converted into a mixture of the useful and not useful energy. For example, gasoline in the car is converted to motion, sound and friction. The later two (sound and friction) are energies but are less useful. Thus, in this case, the energy conversion is not 100 % efficient. Thus, the energy efficiency equation comes into play. This is given as the ratio of the useful energy to the total energy. It is a fraction.
Answer:
Zn(s) + Fe(NO₃)₂(aq) ⇒ Zn(NO₃)₂(aq) + Fe(s)
Explanation:
When metal zinc is added to an iron (II) nitrate solution, we can see the following redox reaction:
Zn(s) + Fe(NO₃)₂(aq) ⇒ Zn(NO₃)₂(aq) + Fe(s)
Zinc is oxidized since its oxidation number increases from 0 to +2.
Iron is reduced since its oxidation number decreases from +2 to 0.
Explanation:
Heat is a form of thermal energy.
Heat is the sum of all the energy of the molecular motion in an object.
Temperature measures the average heat possessed by each molecule in a given substance.
Molecules at a higher temperature possess more kinetic energy and they will move faster. This kinetic energy form is the heat variant of thermal energy.
Temperature is the measure of this heat energy of molecules.
Valency is the number of electrons lost or gained by an atom to attain an stable configuration. Valency is important when writing the formula of chemical compounds in chemistry. Strontium has a valency of 2 while sulfite ion (radicle) has a valency of 2. Therefore, the chemical formula of strontium sulfite is written as SrSO3.
