The correct answer is B. The shape of a molecule where three pairs of electrons are shared is a trigonal planar. This is characterized by one central atom and three atoms forming an equilateral triangle which is bonded to the central atom.
Answer:
C - Magnesium Chloride
Explanation:
The metal in a compounds name is always pronounced, and if the last element is a non-metal, the first half of the element is used and the last part is replaced with "ide"
Answer:
The correct option is;
It contains 6.02 × 10²³ particles of a given substance
Explanation:
A mole of substance is the standard scientific unit of measurement for the quantity of the substance which is made up of a large number of small particles such as molecules, ions, atoms, electrons or other entities.
The General Conference on Weights and Measures defines the mole as the amount of a substance that contains 6.02214076 × 10²³ units of entities
The number 6.02214076 × 10²³, is also known as Avogadro's number.
The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
The Molarity of the solution is given by:
--- (A)
But NaCl, which is a solute, is given in grams.
Therefore, first, we need to convert grams into moles.
Molecular weight of NaCl = 58.44 grams/mole.
So,
117 grams * (moles/ 58.44 grams) =
2.00 moles of NaClNow that we have moles of NaCl, plug in the values in (A):
(A) => Molarity = (2 / 2.7 ) =
0.741 moles/litreThe correct answer is:
0.741 moles/litre = Molarity
