What you need to do is like this:
ΔSrxn∘ = Products - Reactants
<span>ΔSrxn∘ = [NO2 (mols*S∘)] - [NO (mols*S∘) + O2 (mols*S∘)] </span>
<span>ΔSrxn∘ = [(2 mol * 240.0 J/mol*K)] - [(1 mol *205.2 J/mol*K) + (2 mol *210.8 J/mol*K)] </span>
<span>ΔSrxn∘ = [480 J/K] - [626.8 J/K] </span>
<span>ΔSrxn∘ = -146.8 J/K
</span>I hope this is good for you
Answer:
- <u>7.04 × 10²⁴ molecules of Na₂O</u>
Explanation:
<u>1) Balanced chemical equation (given):</u>
- 4 Na(s) + O₂ (g) → 2Na₂O (s)
<u>2) Mole ratio:</u>
<u>3) Number of moles of O₂ in 187 grams of oxygen:</u>
- Molar mass O₂ = 32.00 g/mol
- Number of moles = mass in grams / molar mass = 187 g / 32.00 g/mol = 5.844 mol
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<u>4) Number of moles of Na₂O:</u>
- Proportion: 1 mol O₂ / 2 mol Na₂O = 5.844 mol O₂ / x
- x = 5.844 mol O₂ (2 mol Na₂O / 1 mol O₂) = 11.688 mol Na₂O
<u />
<u>5) Number of molecules</u>
- Number of molecules = number of moles × Avogadro's number
- Number of molecules = 11.688 mol × 6.022 × 10²³ molecules/mol =
= 7.04 × 10 ²⁴ molecules ← answer
The answer is rounded to three significant figures.
Answer:
Al + MnO4- + 2H2O → Al(OH)4- + MnO2
Explanation:
First of all, we out down the skeleton equation;
Al + MnO4- → MnO2 + Al(OH)4-
Secondly, we write the oxidation and reduction equation in basic medium;
Oxidation half equation:Al + 4H2O + 4OH- → Al(OH)4- + 4H2O + 3e-
Reduction half equation:MnO4- + 4H2O + 3e- → MnO2 + 2H2O + 4OH-
Thirdly, we add the two half reactions together to obtain:
Al + MnO4- + 8H2O + 4OH- + 3e- → Al(OH)4- + MnO2 + 6H2O + 3e- + 4OH-
Lastly, cancel out species that occur on both sides of the reaction equation;
Al + MnO4- + 8H2O→ Al(OH)4- + MnO2 + 6H2O
The simplified equation now becomes;
Al + MnO4- + 2H2O → Al(OH)4- + MnO2
Answer:
The units of the rate constant, k, depend on the overall reaction order. The units of k for a zero-order reaction are M/s, the units of k for a first-order reaction are 1/s, and the units of k for a second-order reaction are 1/(M·s).
Explanation:
Answer:
Taking reading of the volume level of liquid in a buret while it is inclined leading to parallax error
Explanation:
Practices that will not help you make accurate volume reading on a buret are
1. Leaving air bubbles buret tip or in the stopcock
2. Error due to parallax: Taking volume reading while looking at the scale of an inclined buret. Looking down the buret gives it an appearance of a higher reading than actual reading while up towards the meniscus will make it look lower than the actual value
3. Pouring in the liquid too rapidly into the buret forming droplets on the inner walls of the buret which can alter the volume reading of the buret when the drops settle into the remaining liquid in the buret
