Caffeine has the following percent composition: carbon 49.48%, hydrogen 5.19%, oxygen 16.48% and nitrogen 28.85%. Its molecular weight is 194.19 g/mol.
PbCr04 + P4O10
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Answer:
Element Symbol Mass Percent
Chlorine Cl 65.571%
Iron Fe 34.429%
Explanation:
Answer : (C) "Higher frequencies have larger spaces between lines".
Explanation:
In Young's experiment, the condition for constructive interference is given by :
.........(1)
n is order or number of lines observed
d is distance between slits
is the angle between the path and the line from screen to the slits.
We also know that, 
or

where,
c is the speed of light
is frequency
is wavelength
So, equation (1) turns into


So,

or
Higher frequencies have larger spaces between line.
So, correct option is (C).
Answer: 250 kJ
Explanation: According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to Hess’s law, the chemical equation can be treated as algebraic expressions and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
(1)
(2)
Net chemical equation:
(3)
Adding 1 and 2 we get,
(4)
Now dividing equation (4) by 4, we get
(4)