Answer:
13 minutes
Explanation:
For the endothermic reaction to reach 0°C, it will take 13 minutes.
Let us follow the process step by step;
Rate of decrease is 2°C per minute.
Start is 26°C
Time temperature
0 min 26°C
1 min 24°C
2 min 22°C
3 min 20°C
4 min 18°C
5 min 16°C
6 min 14°C
7 min 12°C
8 min 10°C
9 min 8°C
10 min 6°C
11 min 4°C
12 min 2°C
13 min 0°C
A molecule has an empirical formula of ch, and its molar mass is known to be 26 g/mol and the molecular formula is C₂H₂ ethyne
Molecular formula of compound is (CH)n and the given molar mass is 26g/mol
Molar mass of (CH)n, C=12=n(12+1)=13n
So 13n and n=2
=13×2=26 and given molar mass is also 26g/mol
So here two carbon and two hydrogen so molecular formula is C₂H₂ and name is ethyne
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Answer:
7.37 mL of KOH
Explanation:
So here we have the following chemical formula ( already balanced ), as HNO3 reacts with KOH to form the products KNO3 and H2O. As you can tell, this is a double replacement reaction,
HNO3 + KOH → KNO3 + H2O
Step 1 : The moles of HNO3 here can be calculated through the given molar mass ( 0.140 M HNO3 ) and the mL of this nitric acid. Of course the molar mass is given by mol / L, so we would have to convert mL to L.
Mol of NHO3 = 0.140 M
30 / 1000 L = 0.140 M
0.03 L = .0042 mol
Step 2 : We can now convert the moles of HNO3 to moles of KOH through dimensional analysis,
0.0042 mol HNO2
( 1 mol KOH / 1 mol HNO2 ) = 0.0042 mol KOH
From the formula we can see that there is 1 mole of KOH present per 1 moles of HNO2, in a 1 : 1 ratio. As expected the number of moles of each should be the same,
Step 3 : Now we can calculate the volume of KOH knowing it's moles, and molar mass ( 0.570 M ).
Volume of KOH = 0.0042 mol
( 1 L / 0.570 mol )
( 1000 mL / 1 L ) = 7.37 mL of KOH
Answer:
Mn^2+(aq) + 4H2O(l) + 5[VO2]^+(aq) + 10H^+(aq) ---------->MnO4^-(aq) + 8H^+(aq) + 5[VO]^2+(aq) + 5H2O(l)
Explanation:
Oxidation half equation:
Mn^2+(aq) + 4H2O(l) ------------> MnO4^-(aq) + 8H^+(aq) + 5e
Reduction half equation:
5[VO2]^+(aq) + 10H^+(aq) + 5e --------> 5[VO]^2+(aq) + 5H2O(l)
Overall redox reaction equation:
Mn^2+(aq) + 4H2O(l) + 5[VO2]^+(aq) + 10H^+(aq) ---------->MnO4^-(aq) + 8H^+(aq) + 5[VO]^2+(aq) + 5H2O(l)
Answer: 8.59 L of oxygen gas are needed to produce 100 kJ of energy at STP
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number
of particles.
Standard condition of temperature (STP) is 273 K and atmospheric pressure is 1 atmosphere respectively.
1 mole of every gas occupy volume at STP = 22.4 L
The balanced chemical reaction is:

3909.9 kJ of of energy is produced by = 
100 kJ of oxygen gas are needed to produce = 