A law stating that the elements are listed in the order of their atomic number
It's not the valences electrons themselves, but the number of valence electrons that determines the chemical properties of an element
Answer:
286.825 or 287
Explanation:
To do this, you need to convert 38.5% to a decimal (0.385) and multiply it by 745.
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Answer:
Ketone
Explanation:
According to the description of the functional group attached to the hydrocarbon - the first and last of a chain of three carbons are each single bonded to 3 hydrogen (H)atoms; the center carbon is double bonded to an oxygen atom, O - it can be deduced that the functional group is a ketone group.
A ketone is a functional group with the structure R₂-C=O, where the two R are alkyl or phenyl groups which may be the same or different. The carbon in a double covalent bond with oxygen is called the carbonyl carbon. The two R groups are bonded to the carbonyl carbon in single covalent bonds.
In the hydrocarbon in this question, the two R groups are methyl groups, CH₃ bonded to the carbonyl carbon. The name of the hydrocarbon is propanone and it is a ketone molecule.
194.5 g of BCl₃ is present in 1 × 10²⁴ molecules of BCl₃.
Explanation:
In order to convert the given number of molecules of BCl₃ to grams, first we have to convert the molecules to moles.
It is known that 1 moles of any element has 6.022×10²³ molecules.
Then 1 molecule will have 
moles.
So 
Thus, 1.66 moles are included in BCl₃.
Then in order to convert it from moles to grams, we have to multiply it with the molecular mass of the compound.
As it is known as 1 mole contains molecular mass of the compound.
As the molecular mass of BCl₃ will be
Mass of boron is 10.811 g and the mass of chlorine is 35.453 g.
Molar mass of BCl₃ = 10.811+(3×35.453)=117.17 g.
So, 194.5 g of BCl₃ is present in 1 × 10²⁴ molecules of BCl₃.
