Find the number of formula units in 30 moles of h3po4

Describe the difference between pure substance and mixtures ( give an example each)

kondaur [170]

Answer:

a pure substance consists only of one element or one compound

a mixture consists of two or more different substances, not chemically joined together.

examples:

pure substance : Hydrogen gas - Diamond - Gold metal.

mixture : water and oil - mixtures of sand and water - trail mix

Explanation:

4 0

2 years ago

Read 2 more answers

Perform the following mathematical operation, and report the answer to the correct number of significant figures. 0.34 x 0.568=?

slavikrds [6]

The correct answer to the problem is 0.193 which is three significant figures.

<h3>What are significant figures?</h3>

The term significant figures has to do with the figures that have a mathematical meaning. We know that the result has to correspond to the highest number of significant figures.

Hence, If we multiply 0.34 x 0.568 the result ought to be recorded as 0.193 which is three significant figures.

Learn more about significant figures:brainly.com/question/14804345

#SPJ1

6 0

1 year ago

a) Whatis the composition in mole fractions of a solution of benzene and toluene that has a vapor pressure of 35 torr at 20 °C?

iogann1982 [59]

Answer:

molar composition for liquid

xb= 0.24

xt=0.76

molar composition for vapor

yb=0.51

yt=0.49

Explanation:

For an ideal solution we can use the Raoult law.

Raoult law: in an ideal liquid solution, the vapor pressure for every component in the solution (partial pressure) is equal to the vapor pressure of every pure component multiple by its molar fraction.

For toluene and benzene would be:

$P_{B}=x_{B}*P_{B}^{o}$

$P_{T}=x_{T}*P_{T}^{o}$

Where:

$P_{B}$ is partial pressure for benzene in the liquid

$x_{B}$ is benzene molar fraction in the liquid

$P_{B}^{o}$ vapor pressure for pure benzene.

The total pressure in the solution is:

$P= P_{T}+ P_{B}$

And

$1=x_{B}+x_{T}$

Working on the equation for total pressure we have:

$P=x_{B}*P_{B}^{o} + x_{T}*P_{T}^{o}$

Since $x_{T}=1-x_{B}$

$P=x_{B}*P_{B}^{o} + (1-x_{B})*P_{T}^{o}$

We know P and both vapor pressures so we can clear $x_{B}$ from the equation.

$x_{B}=\frac{P- P_{T}^{o}}{ P_{B}^{o} - P_{T}^{o}}$

$x_{B}=\frac{35- 22}{75-22} = 0.24$

So

$x_{T}=1-0.24 = 0.76$

To get the mole fraction for the vapor we know that in the equilibrium:

$P_{B}=y_{B}*P$

$y_{T}=1-y_{B}$

So

$y_{B} =\frac{P_{B}}{P}=\frac{ x_{B}*P_{B}^{o}}{P}$

$y_{B}=\frac{0.24*75}{35}=0.51$

$y_{T}=1-0.51=0.49$

Something that we can see in these compositions is that the liquid is richer in the less volatile compound (toluene) and the vapor in the more volatile compound (benzene). If we take away this vapor from the solution, the solution is going to reach a new state of equilibrium, where more vapor will be produced. This vapor will have a higher molar fraction of the more volatile compound. If we do this a lot of times, we can get a vapor that is almost pure in the more volatile compound. This is principle used in the fractional distillation.

7 0

3 years ago

Simple cell?

poizon [28]

Answer:

I don't know..but plz follow me

4 0

3 years ago

In which of the following substances does sharing of electrons between two atoms occur?

malfutka [58]

Answer:- B- $SO_4^-^2$

Explanations:- Sharing of electrons takes place between non metals and the bond formed by the sharing of electrons is known as covalent bond. In first choice we only have a zinc metal and so no sharing of electrons would be possible here.

In third choice we have NaCl. Na is a metal and Cl is a non metal. The property of metals is to transfer its valence electrons to the non metal and the bond formed is known as ionic bond. So, third choice is also not correct.

In choice B we have sulfate ion that has sulfur and oxygen atoms and both of these are non metals. So, sharing of electrons is present here between the S and O atoms and covalent bonds are formed.

So, choice B- $SO_4^-^2$ is the right answer.

6 0

3 years ago