Answer:
a) 
b) 
c) 
Explanation:
The symbols of the isotopes are written like
where,
X is the element
A is the mass number (protons + neutrons)
Z is the atomic number (protons)
<em>a) Iodine-131</em>
The atomic number of iodine is 53. The mass number of this isotope is 131. The symbol is .
<em>b) Iridium-192</em>
The atomic number of iridium is 77. The mass number of this isotope is 192. The symbol is .
<em>c) Samarium-153</em>
The atomic number of samarium is 62. The mass number of this isotope is 153. The symbol is .
Answer:
a salt
Explanation:
compounds are made of molecules but we need to mention the type of compound formed.
Weight percentage of nitrogen can be calculated using the following rule:
weight percentage of nitrogen = (weight of nitrogen / weight of urea) x 100
From the periodic table:
molecular mass of carbon = 12 grams
molecular mass of nitrogen = 14 grams
molecular mass of hydrogen = 1 grams
molecular mass of oxygen = 16 grams
therefore:
mass of nitrogen in urea = 2(14) = 28 grams
mass of urea = 12 + 2(14) + 4(1) + 16 = 60 grams
Substitute with the masses in the equation to get the percentage:
weight percentage of nitrogen = (28/60) x 100 = 46.667%
Answer:
A3B3
Explanation:
Molecular formula = n x empirical formula
(AB) n = 90
MM of AB = 30 g/mol
30n = 90
Divide both side by the coefficient n i.e 30
n = 90/30 = 3
Molecular formula = n x empirical formula
Molecular formula = n x (AB)
Molecular formula = 3(AB) = A3B3
453 divided by 224
density is roughly 2.02 g per ml
as a ml is 1 cm3 density is 2.02 grams per centimeter cubed
