Answer:
The correct answer is option c.
Explanation:
Alkanes with higher molecular mass has higher boiling point.
Thisis because when the molar mass of the alkanes increases the the surface area increases with which van der Waals forces between the molecules of alkane also increase which increases the association of the molecules of with each other which results in increase in boiling point is observed.
The increasing order of the molar mass of the given alkanes;
So out of ethane, pentane and heptane . Heptane has highest molecular mass with higher boiling point value. Where as ethane have the lowest value of boiling point.
Explanation:
To round to a significant figure:
- look at the first non-zero digit if rounding to one significant figure
- look at the digit after the first non-zero digit if rounding to two significant figures
- draw a vertical line after the place value digit that is required
- look at the next digit
- if it's 5 or more, increase the previous digit by one
- if it's 4 or less, keep the previous digit the same
- fill any spaces to the right of the line with zeros, stopping at the decimal point if there is one
<h3>
<em>Hope</em><em> </em><em>it</em><em> </em><em>will</em><em> </em><em>help</em><em> </em><em>you</em><em>.</em><em>.</em><em>.</em><em>.</em><em>.</em></h3>
Answer:
10.8amu
Explanation:
Given parameters:
Abundance of B - 10 = 20% = 0.2
Abundance of B - 11 = 80% = 0.8
Unknown:
Atomic mass of Boron = ?
Solution:
The atomic mass of Boron can be can be calculated using the expression below;
Atomic mass = (abundance of B - 10 x mass of isotope B - 10 ) +( abundance of B - 11 x mass of isotope B- 11)
Atomic mass = (0.2 x 10) + (0.8 x 11) = 2 + 8.8 = 10.8amu
The molecular formula of the liquid : C₆H₁₂
<h3>Further explanation</h3>
Given
molar ratio C H = 1.2 : 0.12
0.12 g at STP gave 32 cm³(0.032 L)
Required
The molecular formula
Solution
At STP, 1 mol = 22.4 L, so for 0.032 L :
mol = 0.032 : 22.4
mol = 0.00143
Molar mass (M) of liquid :
M = mass : mol
M = 0.12 g : 0.00143 mol
M = 83.92≈84 g/mol
C : H = 1 : 2
(CH₂)n=84
(12+2.1)n=84
(14)n=84
n=6
(CH₂)₆=C₆H₁₂
