All categories

3 years ago

Sublimation and boiling both happen at the surface of the substance. a. True b. False

1 answer:

7 0

This statement is: False

Boiling is vaporization that occurs both below and at the surface of the liquid.
However, evaporation happens at the surface of the substance.

So, if you need to correct this statement, the correction would be:
Sublimation and evaporation happen at the surface of the substance.

You might be interested in

You place air in a sealed can at standard temperature and pressure (stp). you heat it to four times its absolute temperature (k)

pochemuha

By Gayle-Lussac's law, the pressure and temperature of a fixed volume and amount of gas is directly proportional.
Thus,

P/T = constant

So if the temperature is increased four times, the pressure is also increased four times.

4 0

3 years ago

What is the average kinetic energy and rms speed of N₂ molecules at STP? Compare these values with those of H₂ molecules at STP.

Otrada [13]

The average kinetic energy and rms speed of N₂ molecules at STP is $5.65686 \times 10^{-21}$ and $493 \mathrm{~m} / \mathrm{s}$

Given,

$\begin{aligned}&\mathrm{P}=1.013 \times 10^{5} \mathrm{~Pa} \\&\mathrm{~T}=273.15 \mathrm{~K} \\&\rho=1.25 \mathrm{~kg} / \mathrm{m}^{3}\end{aligned}$

The average kinetic energy of a molecule is given by, $K . E .=\frac{3}{2} k T$ where k is the Boltzmann constant and Tis the absolute temperature of the gas.

$K . E .=\frac{3}{2} \times $1.380649 \times 10^{-23}$ \times 273.15 K$

$K.E=$5.65686 \times10^{-21}$$

The rms speed of $\mathrm{N}_{2}$ molecules is given by

$\begin{aligned}&\mathrm{V}_{\mathrm{rms}}=\sqrt{\frac{3 \mathrm{RT}}{\mathrm{M}}}=\sqrt{\frac{3 \mathrm{P}}{\rho}} \\&\mathrm{V}_{\mathrm{rms}}=\sqrt{\frac{3 \mathrm{P}}{\rho}} \\&\mathrm{V}_{\mathrm{rms}}=\sqrt{\frac{3 \times 1.013 \times 10^{5}}{1.25}}=493 \mathrm{~m} / \mathrm{s}\end{aligned}$

The average kinetic energy of a gas's particles is inversely related to its temperature. As the gas warms, the particles must travel more quickly since their mass is constant.

The average kinetic energy (K) is equal to one half of the mass (m) of each gas molecule times the RMS speed (vrms) squared.

Learn more about average kinetic energy brainly.com/question/1599923

#SPJ4

6 0

2 years ago

Why wouldn’t a tennis player with two sneakers “bond” to any other tennis players? Why wouldn’t a helium atom with two electrons

aleksklad [387]

Answer:

Explained below.

Explanation:

A tennis player with two sneakers wouldn't bond to any other tennis player because he is already stable and complete with the 2 and doesn't need another players assistance to make him stand well.

However, helium atom with two electrons wouldn't bond to any other atoms because it is stable. This stability arises from the fact that it has two protons and 2 electrons, of which the 2 electrons completely fill its valence shell/outer most shell to make it neutral.

8 0

3 years ago

If the bag was made from a metal (like sturdy aluminum foil), do you think it would lose its heat faster or slower than the plas

Iteru [2.4K]

Answer:

Fish

Explanation:

Because fish and why fish? because fish was one fish so i know this answer is 11

3 0

2 years ago

Consider the following reaction:C2H4(g) + F2(g) -----------> C2H4F2(g) Delta H = -549 kJEstimate the carbon-fluorine bond ene

frutty [35]

Answer:

Bond energy of carbon-fluorine bond is 485 kJ/mol

Explanation:

Enthalpy change for a reaction, is given as:

$\Delta H_{rxn}=\sum [n_{i}\times (E_{bond})_{i}]-\sum [n_{j}\times (E_{bond})_{j}]$

Where $(E_{bond})_{i}$ and $(E_{bond})_{j}$ represents average bond energy in breaking "i" th bond and forming "j" th bond respectively. $n_{i}$ and $n_{j}$ are number of moles of bond break and form respectively.

In this reaction, one mol of C=C, four moles of C-H and one mol of F-F bonds are broken. One mol of C-C bond, four moles of C-H bonds and two moles of C-F bonds are formed

So, $-549kJ=(1mol\times 614kJ/mo)+(4mol\times E_{C-H})+(1mol\times 154kJ/mol)-(1mol\times 347kJ/mol)-(4mol\times E_{C-H})-(2mol\times E_{C-F})$

or, $-549kJ=(1mol\times 614kJ/mo)+(1mol\times 154kJ/mol)-(1mol\times 347kJ/mol)-(2mol\times E_{C-F})$

or, $E_{C-F}=485kJ/mol$

So bond energy of carbon-fluorine bond is 485 kJ/mol

8 0

3 years ago