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4 years ago

Why is it necessary to use models to study submicroscopic objects such as atoms and molecules?

Chemistry

2 answers:

mixas84 [53]4 years ago

7 0

The answer is C. These objects are too small to see.

nadezda [96]4 years ago

7 0

The answer is: C. These objects are too small to see.

For example, ball and stick model gives informations about bond lenght and space filling model gives information about space occupied by atoms.

In chemistry, the ball-and-stick model is a molecular model of a chemical substance which is to display both the three-dimensional position of the atoms and the bonds between them. The atoms are represented by spheres, connected by rods which represent the bonds. Every ball represent one atom in one molecule and they have different colors for different atoms (for example, carbon is black, hydrogen is white, nitrogen is blue).

There also other models: skeletal models, polyhedral models, composite models, computer-based models.

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The reduction in the freezing point of a solution is inversely proportional to a molal concentration

maks197457 [2]

The statement above about "<span>The reduction in the freezing point of a solution is inversely proportional to a molal concentration" is false. It must be directly proportional</span>

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4 years ago

Observe this chemical reaction: <br> 4 Fe + 302– 2Fe2O3<br> How many reactants are there ?

kirza4 [7]

Answer:

2 Reactants

Explanation:

its the iron and oxygen

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3 years ago

Read 2 more answers

Two linear hydrocarbons, Hexane (C6H14) and Heptane (C7H16), form pretty much an ideal solution at any composition. A solution i

Anettt [7]

Answer:

$y_{C_6H_{14}}=0.92$

Explanation:

Hello,

At first, we compute liquid-phase molar fractions:

$n_{C_6H_{14}}=463.96 g*\frac{1mol}{86g} =5.3949molC_6H_{14}\\n_{C_7H_{16}}=667.71 g*\frac{1mol}{100g} =6.6771molC_7H_{16}\\x_{C_6H_{14}}=\frac{5.3949}{5.3949+6.6771} =0.447\\x_{C_7H_{16}}=1-x_{C_6H_{14}}=0.553$

Now, by means of the fugacity concept, for hexane, for instance, we have:

$f_{C_6H_{14}}^V=f_{C_6H_{14}}^L\\y_{C_6H_{14}}p_T=x_{C_6H_{14}}p_{C_6H_{14}}$

In this manner, at 25 °C the vapor pressure of hexane and heptane are 0.198946 atm and 0.013912 atm repectively, thus, the total pressure is:

$p_T=x_{C_6H_{14}}p_{C_6H_{14}}+x_{C_7H_{16}}p_{C_7H_{16}}\\p_T=0.447*0.198946 atm +0.553*0.013912 atm=0.096622atm$

Finally, from the hexane's fugacity equation, we find its mole fraction in the vapour as:

$y_{C_6H_{14}}=\frac{x_{C_6H_{14}}p_{C_6H_{14}}}{p_T}=\frac{0.447*0.198946 atm}{0.096622atm} \\y_{C_6H_{14}}=0.92$

Best regards.

3 0

3 years ago

Read 2 more answers

Sodium and magnesium ions have 10 electrons surrounding their nuclei which ion would you expect to have the larger radius why

Maksim231197 [3]

Sodium because according to the atomic size trend of the periodic table. Elements further to the left are bigger while elements tot he right are smaller. This is also do to their charges, Na has a +1 charge meaning it doesn’t pull the electrons as close as the Mg does with its +2 charge.

8 0

4 years ago

Mg metal reacts with HCl to produce hydrogen gas. Mg(s)+2HCl(aq)→MgCl2(aq)+H2(g) Part A What volume of hydrogen at 0 ∘C and 1.00

Tanzania [10]

Mg(s)+2HCl(aq)→MgCl2(aq)+H2(g)

(since the molar mass of Mg is not given, assuming that it's mola mass is 24gmol¯1)

1st find the moles of Mg using the equation n=m/M where

n - moles

m - mass

M - molar mass

Therefore :

$n \: = 9.45 \:g\div 24g {mol}^{ - 1}$

n = 0.39375mol

n = 0.39mol

Then using the equation n=V/Vm where;

n = mol

V = volume

Vm = molar volume

Find the volume.

n = V/Vm

(n =0.39mol , Vm = 22.4dm³mol¯¹)

V = 0.39mol×22.4dm³mol¯¹

V = 8.736dm³

7 0

3 years ago