Answer:
Explanation:
(a) melting point of S,S-hydrobenzoin should be 140°C. Since S,S-hydrobezoin and R,R-hydrobenzoin are enantiomeric pair so that their melting point and boilong point should be same.
(b) different melting point,
Racemic mixture must have different melting point in comparison to the pure enantiomers.
considering a racemic mixture, individual enantiometer possesses a greater affinity for its kind of molecules than for those of the other enantiometer
Answer:
The main group number for an element can be found from its column on the periodic table.
Explanation:
For example, carbon is in group 4 and has 4 valence electrons. Oxygen is in group 6 and has 6 valence electrons.
Answer:
The water will continue to heat up as the experiment progresses.
Explanation:
When a person's fingers are cold or has a muscles ache, one can use chemical hand warmers to heat them up. There are two types of chemical hand warmer products, and they all depend on exothermic chemical reactions to work.
However, ammonium chloride dissolution is endothermic but its crystalization is exothermic. When used as a hand warner with a calorimeter, it is found that the temperature of the water increases steadily due to the crystalization of the ammonium chloride. Hence the answer.
100% bevause the capital T dominates always
Answers:
See below
Step-by-step explanation:
1. Most food energy
(a) Pringles
Heat from Pringles + heat absorbed by water = 0
m₁ΔH + m₂CΔT = 0
1.984ΔH + 100 × 4.184 × 18 = 0
1.984ΔH + 7530 = 0
ΔH = -7530/1.984 = -3800 J/g
(b) Cheetos
0.884ΔH + 418.4 × 13 = 0
ΔH = -5400/0.884 = -6200 J/g
Cheetos give you more food energy per gram.
(c) Snickers
Food energy = 215 Cal/28 g × 4184 J/1 Cal = 32 000 J/g
The food energy from Cheetos is much less than that from a Snickers bar
2. Experimental uncertainty
The experimental values are almost certainly too low.
Your burning food is heating up the air around it, so much of the heat of combustion is lost to the atmosphere.
3. Percent efficiency
Experimental food energy = 3800 J/g
Actual food energy = 150 Cal/28 g × 4184 J/1 Cal = 22 000 J/g
% Efficiency = Experimental value/Actual value × 100 %
= 3800/22 000 × 100 %
= 17 %
