When organisms and plants died and sank to the bottom of swamps and oceans, brown soil-like materials called peat are formed. Over millions of years, the peat became covered with sand, clay and other minerals and the peat is converted into layers of sedimentary rocks. After a long time, different type of fossil fuels are formed.
Answer:
A. 0.295 mole
B. 0.055 mole
C.0.144 mole
D. 0.03 mole
Explanation:
To find the amount in moles, we simply use a mathematical relation that connects mass, atomic mass and number of moles.
Number of moles = mass/atomic mass
A. Atomic mass of Argon is 40
n = 11.8/40 = 0.295 mole
B. Atomic mass of zinc is 65
n = 3.55/65 = 0.055 mole
C. Atomic mass of Tantalum is 181
n = 26.1/181 = 0.144 mole
D. Atomic mass of lithium is 7
n = 0.211/7 = 0.03 mole
Answer:
Number of molecules = 2.61 x 10²³
Explanation:
Given:
Volume of tetra-chloride = 42 ml
Density = 1.59 g/ml
Find:
Number of molecules
Computation:
Mass = Volume of tetra-chloride x Density
Mass = 42 x 1.59
Mass = 66.78
Molecular mass of tetra-chloride = 154 g/mol
Moles = 66.78 / 154
Moles = 0.4337
0.4337 mole = 0.4337 x Avogadro number
0.4337 mole = 0.4337 x 6.022 x 10²³
Number of molecules = 2.61 x 10²³
