Of the following elements, which could be classified as a metalloid (semimetal)? Select all that apply.

A student weighs an empty flask and stopper and finds the mass to be 55.844 g. She then adds about 5 mL of an unknown liquid and

Oduvanchick [21]

Answer :

(a) The pressure of the vapor in the flask in atm is, 0.989 atm

(b) The temperature of the vapor in the flask in Kelvin is, 372.7 K

The volume of the flask in liters is, 0.2481 L

(c) The mass of vapor present in the flask was, 0.257 g

(d) The number of moles of vapor present are 0.00802 mole.

(e) The mass of one mole of vapor is 32.0 g/mole

Explanation : Given,

Mass of empty flask and stopper = 55.844 g

Volume of liquid = 5 mL

Temperature = $99.7^oC$

Mass of flask and condensed vapor = 56.101 g

Volume of flask = 248.1 mL

Barometric pressure in the laboratory = 752 mmHg

(a) First we have to determine the pressure of the vapor in the flask in atm.

Pressure of the vapor in the flask = Barometric pressure in the laboratory = 752 mmHg

Conversion used :

$1atm=760mmHg$

or,

$1mmHg=\frac{1}{760}atm$

As, $1mmHg=\frac{1}{760}atm$

So, $752mmHg=\frac{752mmHg}{1mmHg}\times \frac{1}{760}atm=0.989atm$

Thus, the pressure of the vapor in the flask in atm is, 0.989 atm

(b) Now we have to determine the temperature of the vapor in the flask in Kelvin.

Conversion used :

$K=273+^oC$

As, $K=273+^oC$

So, $K=273+99.7=372.7$

Thus, the temperature of the vapor in the flask in Kelvin is, 372.7 K

Now we have to determine the volume of the flask in liters.

Conversion used :

1 L = 1000 mL

or,

1 mL = 0.001 L

As, 1 mL = 0.001 L

So, 248.1 mL = 248.1 × 0.001 L = 0.2481 L

Thus, the volume of the flask in liters is, 0.2481 L

(c) Now we have to determine the mass of vapor that was present in the flask.

Mass of flask and condensed vapor = 56.101 g

Mass of empty flask and stopper = 55.844 g

Mass of vapor in flask = Mass of flask and condensed vapor - Mass of empty flask and stopper

Mass of vapor in flask = 56.101 g - 55.844 g

Mass of vapor in flask = 0.257 g

Thus, the mass of vapor present in the flask was, 0.257 g

(d) Now we have to determine the number of moles of vapor present.

Using ideal gas equation:

PV = nRT

where,

P = Pressure of vapor = 0.989 atm

V = Volume of vapor = 0.2481 L

n = number of moles of vapor = ?

R = Gas constant = 0.0821 L.atm/mol.K

T = Temperature of vapor = 372.7 K

Putting values in above equation, we get:

$(0.989atm)\times 0.2481L=n\times (0.0821L.atm/mol.K)\times 372.7K\\\\n=0.00802mole$

Thus, the number of moles of vapor present are 0.00802 mole.

(e) Now we have to determine the mass of one mole of vapor.

$\text{Mass of one mole of vapor}=\frac{\text{Mass of vapor}}{\text{Moles of vapor}}$

$\text{Mass of one mole of vapor}=\frac{0.257g}{0.00802mole}=32.0g/mole$

Thus, the mass of one mole of vapor is 32.0 g/mole

8 0

3 years ago

Composition of the nuclei of two atomic species A and B are given below:

Inessa [10]

Explanation:

(a) mass number = atomic number + number of neutrons

(the atomic number is the number of protons of an element)

mass number of A = 11 + 12 = 23

mass number of B = 17 + 18 = 35

(b) +1 and -1, respectively

(c) A+ + B- → AB (the first plus sign and the minus sign are superscripts)

5 0

2 years ago

I need an example of a chemical change involving water.Pleaseeee.

slava [35]

Chemical change occur when two substances are combined and produces a new substance or decomposes into two or more substances which are entirely different from the original two substances.

There are three types of chemical changes. These are 1) Inorganic Changes, 2) Organic Changes, and 3) Biochemical Changes

Here are some examples of chemicsal changes.

If you combine Sodium and Water, chemical changes causes decomposition into Sodium Hydroxide and Hydrogen.

Sodium + Water ==> Sodium Hydroxide and Hydrogen

Na + H2O ====> NaOH and H

Another example of chemical change is:

Carbon Dioxide and Water will decompose into Sugar and Oxygen

Carbon Dioxide + Water ==> Sugar and Oxygen

CO2 + H2O ==> CnH2nOn (where n is between 3 and 7) and O

7 0

3 years ago

1. Ionization energy is the energy needed to remove an electron from an atom. We can use the periodic table to predict ionizatio

just olya [345]

Ionization energy increases from left to right because the left wants to lose elctrons and the right wants to gain electron

As you go a group it is easier lose lose because the electrons are farther away from the nucleus and there is less attraction from the positive charges.

It should be 3p3. the p level can hold 6 electrons

Rubidium group 1, 1 valence electrons very reactive

Mg2,2 very reactive

Al 3, 3 reactive

6 0

3 years ago

Write the full ground state electron configuration of C − C− . electron configuration: Which neutral atom is isoelectronic with

stepan [7]

Answer: 1. Is2 2s2 2p3

2. Nitrogen

Explanation: The number of electron present In C = 6

But an extra electron is added since the charge on C is -1, this therefore makes the total electron 7.

1. By arrangement, the Electronic configuration is therefore;

Ans: 1s2 2s2 2p3

2. It is explained how C has 7 electrons, we can proceed then.

Neutral atom have atomic number of 7.

The element with atomic number of 7 is;

Ans: NITROGEN

7 0

3 years ago