Given :
10 gram sample of propane( C₂H₈ ).
To Find :
The number of moles of propane in given sample.
Solution :
Molecular mass of propane, M = (2 × 12) + ( 1 × 8 ) gram/mol
M = 32 gram/mol
We know, number of moles is given by :
Number of moles, n = m/M
n = 10/32 mol
n = 0.3125 mol
Therefore, number of moles in given sample is 0.3125 mol.
Answer:
E. 1.5M
Explanation:
because there is total 175.32 g of NaCl dissolved in 2 liter of water, and 58.44 g = 1 mol
so total miles = 175.32/58.32 = 3 moles
now 3 moles are in 2 liter of water, hence one liter contains 3/2= 1.5
Therefore answer is E. 1.5M
Answer:
B. –99 kJ.
Explanation:
We have the following information:
1. C(s) + O₂(g) → CO₂(g);
ΔH = -393 kJ
2. 2CO(g) + O₂ → 2CO₂(g);
ΔH = -588 kJ
Using Hess's Law, Our target equation has C(s) on the left hand side, so we re-write equation 1:
1. C(s) + O₂(g) → CO₂(g);
ΔH = -393 kJ
So, we reverse equation 2 and divide by 2, we have equation 3:
3. CO₂(g) → CO(g) + ½O₂;
ΔH = +294 kJ
That is, change the sign of ΔH and divide by 2. Then we add equations 1 and 3 and their ΔH values.
This gives:
C(s) +½O₂(g) → CO(g);
ΔH = +294 - 393 kJ
= -99 kJ
The standard enthalpy of formation of carbon monoxide is -99 kJ/mol.
Answer:
the rock layers of the Grand Canyon
Explanation:
Steno's law are laws that applied to sedimentary rocks. These laws helps in understanding sedimentary sequences.
Sedimentary rocks are derived from the deposition of pre-existing rocks in basins. In order to understand some important relationships between these rock layers, Steno's law offer a good insight.
Steno's law are often applied when we want to do relative dating of rock layers. Some of the laws are:
- Law of superposition of strata
- Law of original horizontality
- Law of lateral continuity
- Law of inclusion
- Law of fossil and fauna succession
These laws helps to interpret sedimentary rock sequences better.
