All categories

2 years ago

Identify the arrows that show removal of thermal energy when matter changes state.

Chemistry

2 answers:

8090 [49]2 years ago

7 0

Let's identify first the phases of matter inside each of those beakers. The first beaker on the left has a compact shape and has its own volume. So, that must be solid. The middle beaker has a compact shape but it takes the shape of its container. So, that must be liquid. The third beaker on the right is gas because the molecules are far away from each other.

After identifying each states, let's investigate the energy for phase change. Let's start with the arrows pointing to the right. The first arrow to the right is a phase change from solid to liquid. The intermolecular forces in a solid is the strongest among the three phases of matter. So, you would need an input of energy to break them apart into liquid. The same is true for the phase change from liquid to gas. Therefore, all the arrows pointing to the right require an input of energy.

The reverse arrows pointing to the left needs to release energy. The molecules in the gas state are free such that they can travel from one point to another easily. They have the highest amount of energy. So, if you want the molecules to come closer together, you need to remove the energy to keep them in place. Therefore, the arrows pointing to the right require removal of energy.

Phantasy [73]2 years ago

4 0

Answer: the arrows pointing to the right show removal of thermal energy

Explanation: plato

You might be interested in

Las plantas ingieren alimentos del exterior?

xeze [42]

Answer:

yes it is

Explanation:

b bc it is i did the test

7 0

3 years ago

How many miles are in 68 grams of copper 2 hydroxide, Cu (OH)2

BabaBlast [244]

Molar mass Cu(OH)₂ = <span>97.561 g/mol

1 mol --------- 97.561 g
? mol ---------- 68 g

moles = 68 * 1 / 97.561

moles = 68 / 97.561

= 0.6969 moles

hope this helps!</span>

8 0

3 years ago

The following table lists molecular weight data for a polypropylene material. Molecular Weight Range (g/mol) xi wi

nikklg [1K]

Answer:

a) the number-average molecular weight is 32,400 g/mol

b) the weight-average molecular weight is 36,320 g/mol

c) the degree of polymerization is 770

Explanation:

Given the data in the question;

Molecular Mean Number Weight Number Weight

weight average average

(g/mol) Mi(g/mol) xi wi xiMi wiMi

8,000-16,000 12,000 0.07 0.03 840 360

16,000-24,000 20,000 0.15 0.09 3000 1800

24,000-32,000 28,000 0.26 0.21 7280 5880

32,000-40,000 36,000 0.27 0.27 9720 9720

40,000-48,000 44,000 0.18 0.28 7920 12320

48,000-56,000 52,000 0.07 0.12 3640 6240

∑ Mn=32,400 Mw=36,320

so;

a) the number-average molecular weight

Mn = ∑Mixi

so from the table above; summation of Row Mixi

Mn = ∑Mixi = 32,400

Therefore, the number-average molecular weight is 32,400 g/mol

b) the weight-average molecular weight

Mw = ∑Miwi

so from the table above; summation of Row Miwi

Mw = ∑Miwi = 36,320

Therefore, the weight-average molecular weight is 36,320 g/mol

c) the degree of polymerization

the degree of polymerization of polypropylene can be determined using number-average molecular and repeat unit molecular weight.

now, for polypropylene { CH₂ = CH - CH₃ }

the repeat unit consist of 3 carbon atoms and 6 hydrogen atoms

given that;

Atomic weight of Carbon mC = 12.01 g/mol and

Atomic weight of Hydrogen mH = 1.008 g/mol

now we find the repeat unit molecular weight of polypropylene

m = nCmC + nHmH

where n is the number of repeat of atoms

so we substitute

m = ( 3 × 12.01) + ( 6 × 1.008)

m = 36.03 + 6.048

m = 42.078 g/mol

now we calculate the degree of polymerization;

DP = Mn / m

so we substitute

DP = 32,400 / 42.078

DP = 769.9985 ≈ 770

Therefore, the degree of polymerization is 770

3 0

2 years ago

The coolant in automobiles is often a 50/50 % by volume mixture of ethylene glycol, C2H6O2, and water. At 20°C, the density of e

Misha Larkins [42]

Explanation:

Let the volume of the solution be 100 ml.

As the volume of glycol = 50 = volume of water

Hence, the number of moles of glycol = $\frac{mass}{molar mass}$

= $\frac{density \times volume}{molar mass}$

= $\frac{1.1088 \times 50}{62 g/mol}$

= 0.894 mol

Hence, number of moles of water = $\frac{50 \times 0.998}{18}$

= 2.77

As glycol is dissolved in water.

So, the molality = $0.894 \times \frac{1000}{49.92}$

= 17.9

Therefore, the expected freezing point = $-1.86 \times 17.9$

= $-33.31^{o}C$

Thus, we can conclude that the expected freezing point is $-33.31^{o}C$ .

6 0

2 years ago

Elements are organized on the periodic table based on their properties. Which statement correctly predicts and explains the chem

makkiz [27]

A) The alkali metal atoms forms a +1 ion, while the alkaline eaeth metal atom forms a +2 ion.

6 0

3 years ago

Read 2 more answers