There are 2 moles of NA2SO4 present in 284.078 grams of NA2SO4. Why? Well, we already know here that there are 284.078 grams of NA2SO4. To find how many moles are present in this compound, we would have to divide these grams by the molar mass of the compound. When we go to the periodic table of elements, we will find that there are two moles sodium (which represents 45.98 grams), one mole sulfur (which represents 32.06 grams), and four moles oxygen (which represents 64 grams). When combining these, we would get one mole of sodium sulfate which is representative of 142.04 grams total. That is our molar mass. Now that we have the molar mass, we can go back and divide. 284.078 divided by 142.04 is equal to about 1.99999, and that rounds up to 2 moles. Hence, there are 2 moles of NA2SO4 present in 284.078 grams of NA2SO4.
Your final answer: A is your answer.
Answer:
(a) Cu²⁺ +2e⁻ ⇌ Cu
(c) 0.07 V
Explanation:
(a) Cu half-reaction
Cu²⁺ + 2e⁻ ⇌ Cu
(c) Cell voltage
The standard reduction potentials for the half-reactions are+
<u> E°/V
</u>
Cu²⁺ + 2e⁻ ⇌ Cu; 0.34
Hg₂Cl₂ + 2e⁻ ⇌ 2Hg + 2Cl⁻; 0.241
The equation for the cell reaction is
E°/V
Cu²⁺(0.1 mol·L⁻¹) + 2e⁻ ⇌ Cu; 0.34
<u>2Hg + 2Cl⁻ ⇌ Hg₂Cl₂ + 2e⁻; </u> <u>-0.241
</u>
Cu²⁺(0.1 mol·L⁻¹) + 2Hg + 2Cl⁻ ⇌ Cu + Hg₂Cl₂; 0.10
The concentration is not 1 mol·L⁻¹, so we must use the Nernst equation
(ii) Calculations:
T = 25 + 273.15 = 298.15 K
![Q = \dfrac{\text{[Cl}^{-}]^{2}}{ \text{[Cu}^{2+}]} = \dfrac{1}{0.1} = 10\\\\E = 0.10 - \left (\dfrac{8.314 \times 298.15 }{2 \times 96485}\right ) \ln(10)\\\\=0.010 -0.01285 \times 2.3 = 0.10 - 0.03 = \textbf{0.07 V}\\\text{The cell potential is }\large\boxed{\textbf{0.07 V}}](https://tex.z-dn.net/?f=Q%20%3D%20%5Cdfrac%7B%5Ctext%7B%5BCl%7D%5E%7B-%7D%5D%5E%7B2%7D%7D%7B%20%5Ctext%7B%5BCu%7D%5E%7B2%2B%7D%5D%7D%20%3D%20%5Cdfrac%7B1%7D%7B0.1%7D%20%3D%2010%5C%5C%5C%5CE%20%3D%200.10%20-%20%5Cleft%20%28%5Cdfrac%7B8.314%20%5Ctimes%20298.15%20%7D%7B2%20%5Ctimes%2096485%7D%5Cright%20%29%20%5Cln%2810%29%5C%5C%5C%5C%3D0.010%20-0.01285%20%5Ctimes%202.3%20%3D%200.10%20-%200.03%20%3D%20%5Ctextbf%7B0.07%20V%7D%5C%5C%5Ctext%7BThe%20cell%20potential%20is%20%7D%5Clarge%5Cboxed%7B%5Ctextbf%7B0.07%20V%7D%7D)
Answer:
103.3 g
Explanation:
Data Given:
Volume of carbon tetrachloride (v) = 65.0 mL
Density of carbon tetrachloride (d) = 1.59 g/cm³
Solution:
Convert volume of carbon tetrachloride from ml to cm³
1 ml = 1 cm³
so,
65.0 mL = 65.0 cm³
Formula used to calculated mass of carbon tetrachloride should be taken for experiment.
d = m/v
Rearrange the above equation:
m = d x v . . . . . . .(1)
Put values in equation 1
m = 1.59 g/cm³ x 65.0 cm³
m = 103.3 g
Answer: Option (d) is the correct answer.
Explanation:
A reaction in which there occurs change in oxidation state of reacting species is known as an oxidation-reduction reaction.
(a)
Will be written as:

In this reaction, there occurs no change in oxidation state of reacting species. Hence, it is not an oxidation-reduction reaction.
(b) 
Will be written as:

Similarly here, there occurs no change in oxidation state of reacting species. Hence, it is not an oxidation-reduction reaction.
(c) 
Will be written as:

Here, also there occurs no change in oxidation state of reacting species. Hence, it is not an oxidation-reduction reaction.
(d) 
So, here there occurs change in oxidation state of Mg from 0 to +2 and oxidation state of H changes from +1 to 0. Hence, it is an oxidation-reduction reaction.
Thus, we can conclude that
is an oxidation-reduction reaction.