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2 years ago

According to the vsepr theory, which shape represents the molecule, cf4?

1 answer:

3 0

VSEPR is an acronym which stands for Valence Shell Electron Pair Repulsion. The theory is most commonly used as basis for establishing the shapes of the substances.

CF4, as can be seen, has only one carbon atom and four fluorine atoms. The most preferred shape of the chemical is therefore, tetrahedral.

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A set of headphones produces sounds that cancel out sound waves from the

Basile [38]

Answer:

C. Destructive interference

Explanation:

<em>Destructive interference</em> is when there are two waves <u>with the same frequency</u>, and the peaks of one wave (the highest points) line up with the valleys (the lowest points) of the second one.

Constructive interference would cause the sound to be louder.

Absorption and reflection are interactions that would not take into account the fact that the headphones produce sounds.

4 0

3 years ago

Ethanedioic acid, a compound that is present in many vegetables, has a molar mass of 90.04 g/mol and a composition of 26.7% Carb

aleksandrvk [35]

Answer:

Empirical CHO2

Molecular C2H2O4

Explanation:

To determine the formulas, firstly, we need to divide the percentage compositions by the atomic masses.

Kindly note that the atomic mass of carbon, oxygen and hydrogen are 12, 16 and 1 respectively. We proceed with the division as follows:

C = 26.7/12 = 2.225

H = 2.2/1 = 2.2

O = 71.1/16 = 4.44375

We then proceed to divide by the smallest value which is 2.2 in this case

C = 2.25/2.2 = 1

H = 2.2/2.2 = 1

O = 4.44375/2.2 = 2

Thus, the empirical formula is CHO2

We now proceed to get the molecular formula as follows

[12+ 1 + 16(2) ]n = 90.04

45n = 90.04

n = 90.04/45 = 2

The molecular formula is :

C2H2O4

4 0

3 years ago

A sample of CaCO3 (molar mass 100. g) was reported as being 30. percent Ca. Assuming no calcium was present in any impurities, c

natka813 [3]

Answer:

Approximately 75%.

Explanation:

Look up the relative atomic mass of Ca on a modern periodic table:

Ca: 40.078.

There are one mole of Ca atoms in each mole of CaCO₃ formula unit.

The mass of one mole of CaCO₃ is the same as the molar mass of this compound: $\rm 100\; g$ .
The mass of one mole of Ca atoms is (numerically) the same as the relative atomic mass of this element: $\rm 40.078\; g$ .

Calculate the mass ratio of Ca in a pure sample of CaCO₃:

$\displaystyle \frac{m(\mathrm{Ca})}{m\left(\mathrm{CaCO_3}\right)} = \frac{40.078}{100} \approx \frac{2}{5}$ .

Let the mass of the sample be 100 g. This sample of CaCO₃ contains 30% Ca by mass. In that 100 grams of this sample, there would be $\rm 30 \% \times 100\; g = 30\; g$ of Ca atoms. Assuming that the impurity does not contain any Ca. In other words, all these Ca atoms belong to CaCO₃. Apply the ratio $\displaystyle \frac{m(\mathrm{Ca})}{m\left(\mathrm{CaCO_3}\right)} \approx \frac{2}{5}$ :

$\begin{aligned} m\left(\mathrm{CaCO_3}\right) &= m(\mathrm{Ca})\left/\frac{m(\mathrm{Ca})}{m\left(\mathrm{CaCO_3}\right)}\right. \cr &\approx 30\; \rm g \left/ \frac{2}{5}\right. \cr &= 75\; \rm g \end{aligned}$ .

In other words, by these assumptions, 100 grams of this sample would contain 75 grams of CaCO₃. The percentage mass of CaCO₃ in this sample would thus be equal to:

$\displaystyle 100\%\times \frac{m\left(\mathrm{CaCO_3}\right)}{m(\text{sample})} = \frac{75}{100} = 75\%$ .

3 0

2 years ago

20. You are approaching a downhill. Which configuration woulo

LenKa [72]

Answer: I think the answer is A

Explanation:

I’m sorry if I’m wrong.

4 0

2 years ago

How many moles of oxygen will be produced from the decomposition of 3 moles of KClO3?

AlexFokin [52]

Answer:

4.5moles

Explanation:

First, let us balance the equation given from the question. This is illustrated below:

KClO3 —> KCl + O2

There are 2 atoms of O on the right side and 3 atoms on the left. It can be balance by putting 2 in front of KClO3 and 3 in of O2 as shown below

2KClO3 —> KCl + 3O2

Now, we have 2 atoms each of K and Cl on the left side and 1atom each of K and Cl on the right. It can be balance by putting 2 in front of KCl as shown below:

2KClO3 —> 2KCl + 3O2

Now the equation is balanced.

From the balanced equation,

2 moles of KClO3 produced 3 moles of O2.

Therefore, 3 moles of KClO3 will produce = (3 x 3) /2 = 4.5moles of O2.

Therefore 3 moles of KClO3 will produce 4.5 moles of O2

5 0

3 years ago