Answer:
pH = 4.8
Explanation:
A buffer is formed by a weak acid (0.145 M HC₂H₃O₂) and its conjugate base (0.202 M C₂H₃O₂⁻ coming from 0.202 M KC₂H₃O₂). The pH of a buffer system can be calculated using Henderson-Hasselbalch's equation.
![pH = pKa + log\frac{[base]}{[acid]} \\pH = -log(1.8 \times 10^{-5} )+log(\frac{0.202M}{0.145M} )\\pH=4.8](https://tex.z-dn.net/?f=pH%20%3D%20pKa%20%2B%20log%5Cfrac%7B%5Bbase%5D%7D%7B%5Bacid%5D%7D%20%5C%5CpH%20%3D%20-log%281.8%20%5Ctimes%2010%5E%7B-5%7D%20%29%2Blog%28%5Cfrac%7B0.202M%7D%7B0.145M%7D%20%29%5C%5CpH%3D4.8)
Answer:
1.87x10⁻³ M SO₄²⁻
Explanation:
The reaction of SO₄²⁻ with Ba²⁺ (From Ba(NO₃)₂) is:
SO₄²⁻(aq) + Ba²⁺(aq) → BaSO₄(s)
<em>Where 1 mole of SO₄²⁻ reacts per mole of Ba²⁺</em>
<em />
To reach the end point in this titration, we need to add the same moles of Ba²⁺ that the moles that are of SO₄²⁻.
Thus, to find molarity of SO₄²⁻ we need to find first the moles of Ba²⁺ added (That will be the same of SO₄²⁻). And as the volume of the initial sample was 100mL we can find molarity (As ratio of moles of SO₄²⁻ per liter of solution).
<em>Moles Ba²⁺:</em>
7.48mL = 7.48x10⁻³L ₓ (0.0250moles / L) = 1.87x10⁻⁴ moles of Ba²⁺ = Moles of SO₄²⁻
<em>Molarity SO₄²⁻:</em>
As there are 1.87x10⁻⁴ moles of SO₄²⁻ in 100mL = 0.1L, molarity is:
1.87x10⁻⁴ moles of SO₄²⁻ / 0.1L =
<h3> 1.87x10⁻³ M SO₄²⁻</h3>
Answer:
<u>C) 4</u>
Explanation:
<u>The reaction</u> :
- C (s) + 2H₂ (g) ⇒ CH₄ (g)
12g 4g 16g
Hence, based on this we can say that : <u>2 moles of hydrogen gas are needed to produce 16g of methane.</u>
<u />
<u>For 32g of methane</u>
- Number of moles of H₂ = 32/16 × 2
- Number of moles of H₂ = <u>4</u>
It turns chemical into electricity
B) It was transformed into 350 J of heat energy.
Explanation:
The remaining 350J of energy must have been transformed into 350J of heat energy.
A fan works by converting electrical energy into heat energy.
- According to the third law of thermodynamics "no system is 100% efficient". The conversion of the energy from one form to another involves a lost in energy.
- Heat is one very familiar way by which energy can be lost.
- Some component energy is used to heat the fan in the process and it is a wasted energy.
- Friction surfaces a heat energy in this process.
learn more:
Third law of thermodynamics brainly.com/question/3564634
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