Label the following processes as endothermic or exothermic Labe; the following a

Question

Label the following processes as endothermic or exothermic Labe; the following as able to form hydrogen bons or not. For those that are not, explain why. What process occurs when the temperature of a substance at Point A is increased (at constant pressure) until the substances is at Point B? If 26.5 g of water, what is the molarity of the methanol? What is the boiling point of a solution containing 0.852 g naphthalene(C_10H_2, molar mass = 128.2g/mol) didolved in 14.0 g benzene? The boiling point of pure benzene is 80.10 degreeC and the boiling point elevation constant, K_is 2.53 degreeC/m. If an egg's shell is carefully dissolved using an acid, the egg white and yolk will remain intact inside a membrane. If the egg is then placed in distilled water, it will slowly expand until it burts. Why?

Explanation / Answer

1. a) The reaction of butane with O2 is Exothermic process.

b) Melting of gold is Endothermic process.

2. A compound with H to show H-bonding is that the H should be attached to any of these 3 elements - N, O or F these 3 are the most electronegative elements and have a small size, so they involve in H-bonding

a) H2SO4 in water is mainly H3O+ and [SO4]2- but there is a small amount of [HSO4]- that can H bond with Water: S-O-H+....-OH2

b) H3COCH3 C-H only so no H bonding, because H bonding with C atom.

c) CH3COOH molecule has H bonding ( O---- H+)

d) CH4 molecule has no H bonding because H bonding with C atom.

3. Evaporation occurs.

5. Molality of Methanol is 1.126 m.

6. calculated the boiling point ELEVATION

moles napthalene = (0.852 grams napthalene) * (1 mole napthalene / 128.2 grams napthalene) = 0.0066 moles napthalene

molality = moles solute / kilograms solvent
molality = 0.0066 moles napthalene / 0.014 kg benzen
molality = 0.4714 m

T(boiling point elevation) = Kb * m * i
T(boiling point elevation) = (2.53 C/m) * (0.4714 m) * (1)
T(boiling point elevation) = 1.1927 C

Now to calculate the new boiling POINT:

T(new boiling point) = 80.10 C + 1.1927 C = 81.29 C

7. If you now put the egg in distilled water, it will grow in size a lot more due to the much larger water concentration gradient across the membrane. the process of osmosis in action the egg. distilled Water is known as hypotonic, ie. very dilute and contains more water than the egg.

Related Questions

Navigate

• Browse (All)
• Browse L
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.