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4 years ago

Is ice melting in a drink a chemical change?

1 answer:

6 0

Nope, it's a physical change. When ice melts it changes into liquid water, it's still water. Changes in which no new substances are formed are physical changes, hence this is a physical change.

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A 0.04328 g sample of gas occupies 10.0-mL at 294.0 K and 1.10 atm. Upon further analysis, the compound is found to be 25.305% C

stepan [7]

Answer:

The molecular formula of the gas sample = $C_2Cl_2$

Lewis structure is shown in the image below.

The geometry around each carbon atom is linear.

Explanation:

Given that:

Temperature = 294.0 K

V = 10.0 mL = 0.01 L ( 1 mL = 0.001 L )

Pressure = 1.10 atm

Using ideal gas equation as:

$PV=nRT$

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L atm/ K mol

Applying the equation as:

1.10 atm × 0.01 L = n ×0.0821 L atm/ K mol × 294.0 K

⇒n = 0.0004557 mol

Given, mass = 0.04328 g

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$0.0004557\ mole= \frac{0.04328\ g}{Molar\ mass}$

Molar mass of the gas sample = 94.9747 g/mol

Given that:-

% of C = 25.305

Molar mass of C = 12.0107 g/mol

% moles of C = 25.305 / 12.0107 = 2.1069

% of Cl = 74.695

Molar mass of Cl = 35.453 g/mol

% moles of Cl = 74.695 / 35.453 = 2.1069

Taking the simplest ratio for C and Cl as:

2.1069 : 2.1069 = 1 : 1

The empirical formula is = $CCl$

Molecular formulas is the actual number of atoms of each element in the compound while empirical formulas is the simplest or reduced ratio of the elements in the compound.

Thus,

Molecular mass = n × Empirical mass

Where, n is any positive number from 1, 2, 3...

Mass from the Empirical formula = 12 + 35.5 = 47.5 g/mol

Molar mass = 94.9747 g/mol

So,

Molecular mass = n × Empirical mass

94.9747 = n × 47.5

⇒ n = 2

The molecular formula of the gas sample = $C_2Cl_2$

Also,

Valence electrons of carbon = 4

Valence electrons of Chlorine = 7

The total number of the valence electrons = 4*2 + 7*2 = 22

The Lewis structure is drawn in such a way that the octet of each atom in the molecule is complete. So,

The Lewis structure is shown in the image below.

According to the theory, the atoms will form a geometry in such a way that there is minimum repulsion and maximum stability. The carbon atoms are sp hybridized.

So, it is of linear shape.

3 0

4 years ago

What is the mass of the block of iron illustrated below?

Mandarinka [93]

VOLUME= 5cm*10cm*2cm =100cm^3
but density of iron=7.874g/cm^3
mass=7.874g*100 =787.4g
mass of that block = 787.4g

7 0

3 years ago

Read 2 more answers

Danielle is designing a system to help race cars slow safely and rapidly at her local racetrack. The racetrack is a straight, 1,

xeze [42]

Answer:

The answer is C

Explanation:

She should make the parachutes smaller in order to decrease the drag forces on the car and bring it to a stop 400 meters after crossing the finish line.

3 0

3 years ago

Upon combustion, a 0.8009 g sample of a compound containing only carbon, hydrogen, and oxygen produces 1.6004 g CO2 and 0.6551 g

Ede4ka [16]

Answer:

C2H4O

Explanation:

We can get the answer through calculations as follows.

From the mass of carbon iv oxide produced, we can get the number of moles of carbon produced. We first divide the mass by the molar mass of carbon iv oxide. The molar mass of carbon iv oxide is 44g/mol

The number of moles of carbon iv oxide is 1.6004/44 = 0.0364

Since there is only one carbon atom in CO2, the number of moles of carbon is same as above

The mass of carbon in the compound is simply the number of moles multiplied by the atomic mass unit. The atomic mass unit of carbon is 12. The mass of carbon in the compound is thus 12 * 0.0364= 0.4368g

From the number of moles of water, we can get the number of moles of hydrogen. To get the number of moles of water, we need to divide the mass of water by its molar mass. Its molar mass is 18g/mol. The number of moles here is thus 0.6551/18 = 0.0364 mole

But there are 2 atoms of hydrogen in 1 mole of water and thus, the number of moles of hydrogen is 2 * 0.0364= 0.0728

The mass of hydrogen is thus 0.0728* 1 = 0.0728g

The mass of oxygen equals the mass of the compound minus that of hydrogen and that of carbon.

= 0.8009 - 0.0728 - 0.4368 = 0.2913 mole

The number of moles of oxygen is the mass of oxygen divided by its atomic mass unit.

That equals 0.2913/16 = 0.0182 mole

The empirical formula can be obtained by dividing the number of moles of each by the smallest which is that of carbon and oxygen 0.0182

H = 0.0728/0.0182 = 4

C= 0.0364/0.0182 = 2

O= 0.0182/0.0182= 1

The empirical formula is thus C2H4O

3 0

3 years ago

As you move down a column what happens to the ionic radius?

Vera_Pavlovna [14]

The ionic radius increases.

Each time you move down to the next Period, you are adding an extra shell of electrons.

Each shell is further from the nucleus than the one before it, so the .

The image below illustrates the increase in ionic radius as you go down a Group.

6 0

3 years ago