Answer:
B. 0.92 M
Explanation:
Molarity of a solution = number of moles (n) ÷ volume (V)
According to the information provided in this question;
mass of NaCl = 42g
Volume of water = 780mL
Using mole = mass/molar mass
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
mole = 42/58.5
mole (n) = 0.72mol
Volume (V) = 780 mL = 780/1000 = 0.780 L
Hence, molarity = n/V
Molarity = 0.72/0.780
Molarity = 0.923 M
Answer:
is the isotopic notation of the atom
Explanation:
The isotope notation is:

<em>Where a is the mass number = Number of protons + Number of neutrons</em>
<em>b is atomic number = Number of protons</em>
The atomic number define the nature of the atom, the element with atomic number = 15 is phosphorus, P:

a = 15 protons + 16 neutrons = 31
b = 15
is the isotopic notation of the atom.
First, find moles of oxygen gas: (3.01 x10^23 molec.)/(6.02 x10^23) =0.5mol O2
Second, multiply moles by the standard molar volume of a gas at STP:(0.5mol)(22.4L) = 11.2L O2