Answer:
D. The electrochemical reaction of the battery must be reversible.
Explanation:
The batteries are based on the production of an electric flux given by a<u> redox reaction</u>. This reaction is <u>spontaneous</u> and is<u> thermodynamically favored</u>.
Thus, when the reactants to the reaction are finished, the flow of current stops and ends. Therefore, when current is administered from another source, the reaction <u>changes its direction</u> and reagents that were previously consumed begin to occur. Therefore the condition for it to be <u>rechargeable</u> is that the reaction can go <u>forward or backward</u>, that is, it is <u>reversible</u>.
Answer:
a. 2 HgO(s) ⇒ 2 Hg(l) + O₂(g)
b. 0.957 g
Explanation:
Step 1: Write the balanced equation
2 HgO(s) ⇒ 2 Hg(l) + O₂(g)
Step 2: Convert 130.0 °C to Kelvin
We will use the following expression.
K = °C + 273.15
K = 130.0°C + 273.15
K = 403.2 K
Step 3: Calculate the moles of O₂
We will use the ideal gas equation.
P × V = n × R × T
n = P × V/R × T
n = 1 atm × 0.0730 L/0.0821 atm.L/mol.K × 403.2 K
n = 2.21 × 10⁻³ mol
Step 4: Calculate the moles of HgO that produced 2.21 × 10⁻³ moles of O₂
The molar ratio of HgO to O₂ is 2:1. The moles of HgO required are 2/1 × 2.21 × 10⁻³ mol = 4.42 × 10⁻³ mol.
Step 5: Calculate the mass corresponding to 4.42 × 10⁻³ moles of HgO
The molar mass of HgO is 216.59 g/mol.
4.42 × 10⁻³ mol × 216.59 g/mol = 0.957 g
of oxygen at STP would be required to react completely with 38.8g of propane.
<u>Given that :</u>
molar mass of propane = 44 g/mol
mass of propane = 38.8 g
∴ Moles present in 38.8 g of propane =
= 0.88 mole
<u>applying rule of balanced equations </u>
1 mole of propane = 5 moles of oxygen
0.88 mole of propane = 5 * 0.88 = 4.4 moles of oxygen
Note : volume of 1 mole of oxygen at STP = 
∴Total volume of oxygen required at STP = 22.4 * 4.4 = 
Hence we can conclude that the volume of oxygen at STP required to react completely 
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Answer:
Lead is added to warm dilute nitric acid. When the carbonate has reacted with the warm acid, more carbonate is added until the carbonate is in excess.
Explanation: