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2 years ago

Which of these statements is not necessarily true for two objects in thermal equilibrium?

Chemistry

1 answer:

Dmitrij [34]2 years ago

5 0

1. Answer: C. The objects' temperatures have both changed by the same amount.

Explanation:

An object is said to be in thermal equilibrium when the objects have attained same temperature. Heat transfer from hotter object to colder one in contact takes place until the temperature of the two are equal. It is not necessary that the temperature of both the objects changes by same amount. After attainment of thermal equilibrium, the temperature of the objects stop changing and the tiny particles of the object move at the same rate.

Hence, the objects' temperatures have both changed by the same amount. is not necessarily true for two objects in thermal equilibrium.

2. Answer: C. Objects are made of tiny particles, and their motion depends on the temperature.

Explanation:

Kinetic theory of heat states that the kinetic energy of constituent particles determine the temperature of the object. The statement that best explains this is Objects are made of tiny particles, and their motion depends on the temperature.

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An increase in temperature will effect vapor pressure by:

-BARSIC- [3]

Answer: Increases.

Explanation: As the temperature of a liquid or solid increases its vapor pressure also increases. Conversely, vapor pressure decreases as the temperature decreases.

5 0

2 years ago

A gas sample occupies 3.50 liters of volume at 20.°c. what volume will this gas occupy at 100.°c (reported to three significant

VLD [36.1K]

Explanation:

According to Charle's law, at constant pressure the volume of an ideal gas is directly proportional to the temperature.

That is, $Volume \propto Temperature$

Hence, it is given that $V_{1}$ is 3.50 liters, $T_{1}$ is 20 degree celsius, and $T_{2}$ is 100 degree celsius.

Therefore, calculate $V_{2}$ as follows.

$\frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}$

$\frac{3.50 liter}{20^{o}C} = \frac{V_{2}}{100^{o}C}$

$V_{2}$ = 17.5 liter

Thus, we can conclude that volume of gas required at 100 degree celsius is 17.5 liter.

6 0

2 years ago

Read 2 more answers

A precipitate forms when mixing solutions of sodium fluoride (NaF) and lead II nitrate (Pb(NO3)2). Complete and balance the net

Margarita [4]

Answer:

Pb^2+(aq) + 2F-(aq) → PbF2(s)

Explanation:

Step 1: Data given

sodium fluoride = NaF

lead(II)nitrate Pb(NO3)2

Step 2: The unbalanced equation

NaF(aq) + Pb(NO3)2(aq) → PbF2(s) + NaNO3(aq)

Step 3: Balancing the equation

NaF(aq) + Pb(NO3)2(aq) → PbF2(s) + NaNO3(aq)

On the left side we have 2x NO3 (in Pb(NO3)2), on the right side we have 1x NO3 (in NaNO3). To balance the amount of NO3 we hvae to multiply NaNO3 on the right side by 2.

NaF(aq) + Pb(NO3)2(aq) → PbF2(s) + 2NaNO3(aq)

On the left side we have 1x Na (in NaF), on the right side we have 2x Na (in 2NaNO3). To balance the amount of Na we have to multiply NaF on the left side by 2. Now the equation is balanced.

2NaF(aq) + Pb(NO3)2(aq) → PbF2(s) + 2NaNO3(aq)

Step 4: Calculate net ionic equation

The net ionic equation, for which spectator ions are omitted - remember that spectator ions are those ions located on both sides of the equation - will , after canceling those spectator ions in both side, look like this:

2Na+(aq) + 2F-(aq) + Pb^2+(aq) + 2NO3-(aq) → PbF2(s) + 2Na+(aq) + NO3-(aq)

Pb^2+(aq) + 2F-(aq) → PbF2(s)

4 0

2 years ago

A 20.0-mL sample of lake water was acidified with nitric acid and treated with excess KSCN to form a red complex (KSCN itself is

Novosadov [1.4K]

Answer:

8.09x10⁻⁵M of Fe³⁺

Explanation:

Using Lambert-Beer law, the absorbance of a sample is proportional to its concentration.

In the problem, the Fe³⁺ is reacting with KSCN to produce Fe(SCN)₃ -The red complex-

The concentration of Fe³⁺ in the reference sample is:

4.80x10⁻⁴M Fe³⁺ × (5.0mL / 50.0mL) = 4.80x10⁻⁵M Fe³⁺

Because reference sample was diluted from 5.0mL to 50.0mL.

That means a solution of 4.80x10⁻⁵M Fe³⁺ gives an absorbance of 0.512

Now, as the sample of the lake gives an absorbance of 0.345, its concentration is:

0.345 × (4.80x10⁻⁵M Fe³⁺ / 0.512) = 3.23x10⁻⁵M.

As the solution was diluted from 20.0mL to 50.0mL, the concentration of Fe³⁺ in Jordan lake is:

3.23x10⁻⁵M Fe³⁺ × (50.0mL / 20.0mL) = 8.09x10⁻⁵M of Fe³⁺

4 0

2 years ago

Identify the nuclide produced when plutonium-239 decays by alpha emission: 239 94pu→42he + ? express your answer as an isotope u

Galina-37 [17]

1. Answer is ₉₂²³⁵U

Since this is an alpha emission the atomic number of the daughter nucleus decreases by 2 while mass number decreases by 4 compared to parent atom. Since parent atom has 94 as atomic number the daughter atom should have 94 - 2 = 92 as atomic number and 239 - 4 = 235 as mass number. 

₉₄²³⁹Pu → ₂⁴He + ₉₂²³⁵U

2. Answer is ₉₁²³⁴Pa

Since this is a beta emission, a neutron is converted into a proton while emitting an electron. Hence atomic number increases by 1 compared to mass number but mass number remains as same. Hence, the atomic number of the daughter atom should be 90 + 1 = 91 which belongs to Pa. But the mass number is same as 234.

₉₀²³⁴Th → ₋₁⁰e + ₉₁²³⁴Pa

3. Answer is ₈¹⁸O

Since this is a positron emission, a proton is converted into a neutron while emitting an positron. Hence atomic number decreases by 1 compared to mass number but mass number remains as same. Hence, the atomic number of the daughter atom should be 9- 1 = 8 which belong to O. But the mass number is same as 18.

₉¹⁸F → ₊₁⁰e + ₈¹⁸O

4. Answer is ₈₀²⁰¹Hg

This is an electron capture decay. A proton is converted into a neutron by emitting a gamma ray. In this process mass number remains as same as parent atom which is 201, but the atomic number is decreased by 1 than parent atom. Hence atomic number of daughter nucleus is 81 -1 = 80 which belongs to Hg.

₈₁²⁰¹Tl + ₋₁⁰e → ₀⁰γ + ₈₀²⁰¹Hg

6 0

2 years ago