When converting from moles to molecules OR molecules to moles you use what quantitative value?

According to the electron sea theory, what happens when a collection of metal atoms are in close proximity to each other?

lys-0071 [83]

The correct answer is A. All electrons become free and separate from the nuclei. In metallic bonds, the electrons of the metal atoms are delocalized. The electron in the electron sea can freely roam around or are free to flow.

8 0

3 years ago

The ratio of nitrogen to oxygen by mass in NO is 7.0:8.0. Identify the ratio of nitrogen to oxygen by mass in NO2 and N2O7 .

Rus_ich [418]

This problem is providing the ratio of nitrogen to oxygen by mass in nitrogen monoxide, NO, as 7.0:8.0 and asks for the same ratio but in NO₂ and N₂O₇. After doing the calculations, the results are 7.0:16.0 and 1.0:4.0 respectively.

<h3>Mass ratios:</h3>

In chemistry, one can calculate the mass ratios in chemical formulas according to the atomic mass of each atom. In such a way, one knows the mass ratio of nitrogen to oxygen in NO is 7.0:8.0 because we divide the atomic mass of nitrogen by oxygens:

$\frac{14}{16}=\frac{7.0}{8.0}$

Now, for chemical formulas with subscripts, one must multiply the atomic mass of the element by the subscript in the formula, which is the case of NO₂ and N₂O₇ as shown below:

$NO_2:\frac{14}{16*2}=\frac{14}{32} =\frac{7.0}{16.0} \\
\\
N_2O_7:\frac{14*2}{16*7}=\frac{28}{112} =\frac{1.0}{4.0}$

Therefore, the results for NO₂ and N₂O₇ are 7.0:16.0 and 1.0:4.0 respectively

Learn more about atomic masses: brainly.com/question/5566317

3 0

2 years ago

Solids, liquids, and gases are three common states of matter. Which of these states of matter can flow?

Mademuasel [1]

Liquid it would be liquid

5 0

2 years ago

Read 2 more answers

What does the frequency of a wave represent? A. the distance between two consecutive crests B. the number of wave cycles that pa

zepelin [54]

The frequency of a wave represents B. the number of wave cycles that pass through a specific point within a given time.

The distance between two consecutive crests and the length of a wave are the wavelength.

The distance between the highest and lowest points of a wave is twice the amplitude.

6 0

3 years ago

A 5.000 g mixture contains strontium nitrate and potassium bromide. Excess lead(II) nitrate solution is added to precipitate out

scZoUnD [109]

Answer: The mass percent of potassium bromide in the mixture is 9.996%

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For lead (II) bromide:

Given mass of lead (II) bromide = 0.7822 g

Molar mass of lead (II) bromide = 367 g/mol

Putting values in equation 1, we get:

$\text{Moles of lead (II) bromide}=\frac{0.7822g}{367g/mol}=0.0021mol$

The chemical equation for the reaction of lead (II) nitrate and potassium bromide follows:

$2KBr+Pb(NO_3)_2\rightarrow PbBr_2+2KNO_3$

By Stoichiometry of the reaction:

1 mole of lead (II) bromide is produced from 2 moles of potassium bromide

So, 0.0021 moles of lead (II) bromide will be produced from = $\frac{2}{1}\times 0.0021=0.0042mol$ of potassium bromide

Now, calculating the mass of potassium bromide by using equation 1, we get:

Molar mass of KBr = 119 g/mol

Moles of KBr = 0.0042 moles

Putting values in equation 1, we get:

$0.0042mol=\frac{\text{Mass of KBr}}{119g/mol}\\\\\text{Mass of KBr}=0.4998g$

To calculate the percentage composition of KBr in the mixture, we use the equation:

$\%\text{ composition of KBr}=\frac{\text{Mass of KBr}}{\text{Mass of mixture}}\times 100$

Mass of mixture = 5.000 g

Mass of KBr = 0.4998 g

Putting values in above equation, we get:

$\%\text{ composition of KBr}=\frac{0.4998g}{5.000g}\times 100=9.996\%$

Hence, the percent by mass of KBr in the mixture is 9.996 %

5 0

3 years ago