Methane is a tetrahedral molecule where each C-H is kept as far away from the others as possible due to electron-electron repulsion, resulting in a bond angle of 109.5˚ (Technically 109˚ 28' but I would just use the decimal version if I were you).
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Answer: 1145.8 years
Explanation:
Half-life of carbon-14 = 5720 years
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the age of the sample:
Expression for rate law for first order kinetics is given by:
where,
k = rate constant = 
t = age of sample = ?
a = let initial amount of the reactant = 100 g
x = amount decayed = 75 g
a - x = amount left after decay process = 100 - 75 = 25g
Now put all the given values in above equation, we get
Answer:
Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.
Answer and Explanation:
The Fremy salt is a chemical compound its chemical name is disodium nitrosodisuphonate
The molecular formula of the Fremy salt is 
When phenol is treated with Fremy salt in presence of water then benzoquinone is formed
( in presence of Fremy salt and water)
C. both a and b
If a light bulb can last longer with the same amount of energy it is given, that means it can use less energy to do the same job compared to one that does not last longer with the same amount of energy it is given. It is much like how a more fuel efficient car will be able to go farther on the same tank of gas, but if you pair it with a car that doesn't have as great of an mpg, when they go the same distance, the car with the greater mpg spends less fuel.
If you don't have to use the energy when you aren't utilizing it, then you can conserve the energy for when you do need it.
