Explanation:
(a) mass number = atomic number + number of neutrons
(the atomic number is the number of protons of an element)
mass number of A = 11 + 12 = 23
mass number of B = 17 + 18 = 35
(b) +1 and -1, respectively
(c) A+ + B- → AB (the first plus sign and the minus sign are superscripts)
Answer:
2.895*10^24
Explanation:
mass of Oxygen give = 153.9g
molar mass of O2 molecule = 16*2=32g/mol
n= mole
To find the mole
n= mass/ molar mass
n= 153.9/32
n=4.81mol.
To find the number of molecules of o
Nm= number of molecule
Nn = Number of mole
NA = number of Avogados
Nm= Nn * NA
Nm= 4.81 *6.02*10^23
Nm= 2.895*10^24
1. You can use Avogadro’s number, 6.022x10^23 atoms/mole, to answer this one.
(3.311x10^24/6.022x10^23) = 5.498 moles of substance
2. H2O has a formula weight approximately equal to 18 grams. Dividing the given amount by the formula weight of water will tell us the number of moles present.
126/18 = 7 moles H2O
Answer:
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