We first calculate the heat released:
Specific heat = 3.21 kJ/kgK
Heat released = heat absorbed by calorimeter
Heat absorbed = mcΔT
= 1.9 x 3.21 x 4.542
= 27.7 kJ
Now, we calculate the moles of hexane present:
Moles = mass / Mr
moles = 0.58 / (12 x 6 + 14)
= 0.0067
Heat of combustion = 27.7 / 0.0067 kJ/mol
ΔH(combustion) = 4,134.3 kJ / mol
Answer:
Boiling point: 63.3°C
Freezing point: -66.2°C.
Explanation:
The boiling point of a solution increases regard to boiling point of the pure solvent. In the same way, freezing point decreases regard to pure solvent. The equations are:
<em>Boiling point increasing:</em>
ΔT = kb*m*i
<em>Freezing point depression:</em>
ΔT = kf*m*i
ΔT are the °C that change boiling or freezing point.
m is molality of the solution (moles / kg)
And i is Van't Hoff factor (1 for I₂ in chloroform)
Molality of 50.3g of I₂ in 350g of chloroform is:
50.3g * (1mol / 253.8g) = 0.198 moles in 350g = 0.350kg:
0.198 moles / 0.350kg = 0.566m
Replacing:
<em>Boiling point:</em>
ΔT = kb*m*i
ΔT = 3.63°C/m*0.566m*1
ΔT = 2.1°C
As boiling point of pure substance is 61.2°C, boiling point of the solution is:
61.2°C + 2.1°C = 63.3°C
<em>Freezing point:</em>
ΔT = kf*m*i
ΔT = 4.70°C/m*0.566m*1
ΔT = 2.7°C
As freezing point is -63.5°C, the freezing point of the solution is:
-63.5°C - 2.7°C = -66.2°C
Answer:
pH = 4.4
Explanation:
pH = -log[H₃O⁺]
= -log(4.3 × 10⁻⁵)
pH = 4.37 = 4.4
I'm actually learning this in my chemistry class right now lol. Hope this helps though. :)
The answer is B.
A cannot be the answer because only electrons move around the nucleus.
C cannot be it because electrons have a lot more mass than neutrons.
D can't be it because it 's not a typical occurrence for the amount of neutrons to equal the amount of electrons
Answer: Boron is the element which has properties of both metals and nonmetals.
Explanation:
Metals are defined as the elements which loose electrons to attain stable electronic configuration. They attain positive charge and form cation. Example: Zinc (Zn), Aluminium (Al) , copper (Cu)
Non-metals are defined as the elements which gain electrons to attain stable electronic configuration. They attain negative charge and form anion. Example: Chlorine (Cl) , Sulphur (S)
Metalloids are defined as the elements which show properties of both metals and non-metals. There are 7 metalloids in the periodic table. They are Boron (B) , Silicon (Si) , Germanium (Ge) , Arsenic (As) , Antimony (Sb), Tellurium (Te) and Polonium (Po).
Thus boron is the element which has properties of both metals and nonmetals.
