It'd be a physical change. This is because it's a change in the state of matter and not altering the chemical structure of water
The correct options are as follows:
1. A.
A synthesis reaction is a type of reaction in which two or more reactants combine together to form only one product. Synthesis reaction always release energy in form of light and heat, therefore, they are usually exothermic reactions. In the option given in A, nitrogen and nitrogen combine together to form ammonia; this is a synthesis reaction.
2. D
A radioactive half life refers to the amount of time it will take for half of an original radioactive isotope to decay.
In the question given above, the half life of the element is 1000. Thus, in 1000 years only half of the original amount will remain. In another 1000 years only 1/4 of the original amount will remain and in another 1000 years only 1/8 of the original amount will remain. Therefore, it will take 3 half lives before 1/8 of the original sample remain.<span />
The concept we are looking for here is electronegativity. This concept is a measure of how strong an atom or element can attract a pair, that is bonding, of electrons to itself.
Fluorine is the element or atom of the greatest electronegativity. Electronegativity would increase as we move left to right of the periodic table.
Answer:
MgBr2 < MgCl2 < NaBr < NaCl
Explanation:
In order to determinate ionic character, we have to subtract the electronegativity from the elements involved. This is known as Pauling rule.
MgBr2 > ΔΕΝ = 1.8
NaCl > ΔΕΝ = 2.3
MgCl2 > ΔΕΝ = 2
NaBr > ΔΕΝ = 2.1
I believe it to be g/mol of Calcium carbonate
because to finde mass...u must have grams(g) as units....
it is the only one that have g as units
as for the first answer the avogadros number gives u the number of atoms in one mole of calcium carbonate....
the second one is based on ... At s.t.p one mole of gas occupies 22.4 dm³⇒to find volume
