4.2 g of hydrogen is required to release 1.2 x 10^3 kJ of heat.
Given from the question that 1 mole of hydrogen gas contains 2 g of hydrogen gas.
We also know that heat of combustion per mole of hydrogen gas –285.8 kJ.
From the question, we are told that heat released by the reaction is -1.2 x 10^3 kJ of heat.
Hence;
If 2g of hydrogen releases –285.8 kJ of heat
x g of hydrogen releases -1.2 x 10^3 kJ of heat
x g = 2g x -1.2 x 10^3 kJ / –285.8 kJ
xg = 4.2 g of hydrogen
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Answer:
Samples A and B are mixtures
Explanation:
For sample A, we were told that the initial density of the solution is 0.77/gmL. After distillation, the liquid left has a density of 1.04/gmL. Apparently, A is a mixture of liquids.
As for sample B, the spread of the chromatogram resulting in different colours show that the sample B is not pure. It is a mixture of substances. A pure sample will yield only a single spot.
I am assuming that the balanced equation is
2H₂ + O₂ ⇒ 2H₂O
Since the hydrogen is the limiting reagent (meaning if the hydrogen runs out the reaction stops), we need to compare the mole ratio between hydrogen and water.
The mole ratio between H₂ and H₂O is 2:2, or 1:1 (as seen on the coefficients of the balanced equation)
And so for every mole of hydrogen, it will be equal to water. Since hydrogen is 4 moles, 4 moles of water would be created.
So we use the coefficients of H₂ and H₂O in order to answer this question.
Answer:
See explaination
Explanation:
CBR (Cosmic Background Radiation)-
Uniform energy that is heard everywhere in the universe. It supports the Big Bang Theory because we can assume that it also started in the same place.
Hubble's Law-
Hubble's Law states that the planets are getting farther away from eachother, therefore, the universe is expanding and must have started as a smaller piece.
Answer:
B. ADDITION OF TWO GROUPS ACROSS A DOUBLE BOND
Explanation:
Addition reaction of alkenes involves the conversion of the double bond in alkenes Inyo single bonds by the addition of two groups of atoms or radicals.
During this addition reaction, two substances, an unsaturated compound(e.g. ethane) and an attacking reagent (hydrogen, halogens, hydrogen halides, chlorine and bromine water) combines to form a single new compound without forming any other products. So a saturated product or one in which is an increase in degree of saturation is formed.
