Please answer 11 and 12, I'm not sure of my answers and I'm gonna be tested on this tomorrow. Thanks!

Which of the statements about elements is true?

Jet001 [13]

1. No two elements have the same kind of atom.

Explanation:

The correct of all statement is that no two elements have the same kind of atoms.

Every element have different atoms.

Over a hundred elements have been identified by scientists.
Atoms are the smallest particles that takes part in chemical reactions.
Elements are distinct substances that cannot be split.
Atoms of all elements do not have the same mass and volume. Isotopes are examples.
It is true that atoms of all elements have different masses and also different volumes.
The volume of an atom is function of the number of electrons it contains.

learn more:

Dalton model of the atom brainly.com/question/1979129

#learnwithBrainly

3 0

3 years ago

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2. Soil is made of <br> A. air<br> B. rocks<br> C. decomposed leaves<br> D. all of the above

Irina18 [472]

Answer:

B

Explanation:

<h2>Soil is a mixture of </h2><h2 /><h2>tiny particles of rock,</h2>

<h2>dead plants and animals </h2>

<h2>,air and water.</h2>

3 0

3 years ago

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If a tractor trailer and a car are both traveling 50km/h when they hit which will have the greatest change in speed and directio

den301095 [7]

The tractor trailer will push the car when they hit so therefore the car will have to greatest change

4 0

3 years ago

When 0.42 g of a compound containing C, H, and O is burned completely, the products are 1.03 g CO2 and 0.14 g H2O. The molecular

Luda [366]

<u>Answer:</u> The empirical and molecular formula for the given organic compound is $C_2H_2O_4$ and $C_6H_4O_2$

<u>Explanation:</u>

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

$C_xH_yO_z+O_2\rightarrow CO_2+H_2O$

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of $CO_2=1.03g$

Mass of $H_2O=0.14g$

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

<u>For calculating the mass of carbon:</u>

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 1.03 g of carbon dioxide, $\frac{12}{44}\times 1.03=0.28g$ of carbon will be contained.

<u>For calculating the mass of hydrogen:</u>

In 18g of water, 2 g of hydrogen is contained.

So, in 0.14 g of water, $\frac{2}{18}\times 0.14=0.016g$ of hydrogen will be contained.

Mass of oxygen in the compound = (0.42) - (0.28 + 0.016) = 0.124 g

To formulate the empirical formula, we need to follow some steps:

<u>Step 1:</u> Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{0.28g}{12g/mole}=0.023moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{0.016g}{1g/mole}=0.016moles$

Moles of Oxygen = $\frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{0.124g}{16g/mole}=0.00775moles$

<u>Step 2:</u> Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.00775 moles.

For Carbon = $\frac{0.023}{0.00775}=2.96\approx 3$

For Hydrogen = $\frac{0.016}{0.00775}=2.06\approx 2$

For Oxygen = $\frac{0.00775}{0.00775}=1$

<u>Step 3:</u> Taking the mole ratio as their subscripts.

The ratio of C : H : O = 3 : 2 : 1

Hence, the empirical formula for the given compound is $C_3H_{2}O_1=C_3H_2O$

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is :

$n=\frac{\text{molecular mass}}{\text{empirical mass}}$

We are given:

Mass of molecular formula = 108.10 g/mol

Mass of empirical formula = 54 g/mol

Putting values in above equation, we get:

$n=\frac{108.10g/mol}{54g/mol}=2$

Multiplying this valency by the subscript of every element of empirical formula, we get:

$C_{(3\times 2)}H_{(2\times 2)}O_{(1\times 2)}=C_6H_4O_2$

Thus, the empirical and molecular formula for the given organic compound is $C_3H_2O$ and $C_6H_4O_2$

6 0

3 years ago

1. Which of the following equations is balanced?

pantera1 [17]

The answer would be A

6 0

3 years ago