Polarity of a molecule doesn't depend only on the presence of certain atom(s). It also depends on symmetry. For example, take the alkanes family
. These molecules are generally nonpolar, because there is no net dipole moment. Now, dipole moment arises due to <span>difference in the electronegativity of carbon and the other element. In organic chemistry, generally these atoms are Oxygen, Halogens, Nitrogen. Because of their high electronegativity, they cause a net dipole moment resulting in polarity.
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is symmetrical and hence non-polar.
is asymmetrical and polar. It's structure is bent because of oxygen lone pairs.
Mass of methanol (CH3OH) = 1.922 g
Change in Temperature (t) = 4.20°C
Heat capacity of the bomb plus water = 10.4 KJ/oC
The heat absorbed by the bomb and water is equal to the product of the heat capacity and the temperature change.
Let’s assume that no heat is lost to the surroundings. First, let’s calculate the heat changes in the calorimeter. This is calculated using the formula shown below:
qcal = Ccalt
Where, qcal = heat of reaction
Ccal = heat capacity of calorimeter
t = change in temperature of the sample
Now, let’s calculate qcal:
qcal = (10.4 kJ/°C)(4.20°C)
= 43.68 kJ
Always qsys = qcal + qrxn = 0,
qrxn = -43.68 kJ
The heat change of the reaction is - 43.68 kJ which is the heat released by the combustion of 1.922 g of CH3OH. Therefore, the conversion factor is:
The answer is 34.1 mL.
Solution:
Assuming ideal behavior of gases, we can use the universal gas law equation
P1V1/T1 = P2V2/T2
The terms with subscripts of one represent the given initial values while for terms with subscripts of two represent the standard states which is the final condition.
At STP, P2 is 760.0torr and T2 is 0°C or 273.15K. Substituting the values to the ideal gas expression, we can now calculate for the volume V2 of the gas at STP:
(800.0torr * 34.2mL) / 288.15K = (760.0torr * V2) / 273.15K
V2 = (800.0torr * 34.2mL * 273.15K) / (288.15K * 760.0torr)
V2 = 34.1 mL
Which two solutions, when mixed together, will undergo a double replacement reaction and form a white, solid substance?
1. NaCl(aq) and LiNO3(aq)
2. KCl(aq) and AgNO3(aq) answer
3. KCl(aq) and LiCL(aq)
4. NaNO3(aq) and AgNO3(aq)
2 is the answer because AgCl is formed and that is a white ppt.
<span>1 mole of benzene (78g) requires 30.8 kJ/ of heat, so 11.5g will need ..... (it's a proportion calculation.) Temperature does not change at BPt and is not relevant if the temp of the liquid is already at the BPt
ne definition of entropy is qrev/T, where qrev is the heat added in reversible operation (for complicated reasons pertaining to heat as a path function) and T is the temperature at which this is done.
Phase changes are particularly good examples for calculations of changes in entropy, since temperature will not change will the bonds of a state are being broken.
The calculations required boils down to:
1) finding the moles of benzene given from molar mass.
2) multiplying that moles by the heat of vaporization.
3)diving the heat energy required by the temperature of boiling point.</span>
