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2 years ago

What is the difference between an element, compound and mixture?

1 answer:

6 0

A compound is considered a pure substance meaning there is only one type of particle in the substance. A mixture is a combination of two or more different chemical pot compound or an element or substances. It is not a pure substance but I combination of multiple particles

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4. Energy can be conserved by -

mart [117]

Energy can be conserved by efficient energy use.

Answer: Option A

Explanation:

Energy can be transferred from one form to another, but it cannot be destroyed or created. So it can be conserved if efficiently used. Thus efficient usage of energy lead to conservation of energy. Due to conservation of energy, the forces can be renewable and non-renewable.

So, we should know how the input energy can be completely converted to another form of energy leading to efficient usage of energy without any loss. As if there is no loss, input energy will be equal to output energy leading to 100% efficiency.

4 0

3 years ago

Combustion analysis of a 13.42-g sample of the unknown organic compound (which contains only carbon, hydrogen, and oxygen) produ

kirza4 [7]

Answer: The molecular formula for the given organic compound is $C_{18}H_{20}O_2$

Explanation:

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 $CO_2=39.61g$

Mass of $H_2O=9.01g$

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

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

So, in 39.61 g of carbon dioxide, $\frac{12}{44}\times 39.61=10.80g$ of carbon will be contained.

For calculating the mass of hydrogen:

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

So, in 9.01 g of water, $\frac{2}{18}\times 9.01=1.00g$ of hydrogen will be contained.

Mass of oxygen in the compound = (13.42) - (10.80 + 1.00) = 1.62 g

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

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{10.80g}{12g/mole}=0.9moles$

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

Moles of Oxygen = $\frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{1.62g}{16g/mole}=0.10moles$

Step 2: 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 0.10 moles.

For Carbon = $\frac{0.9}{0.10}=9$

For Hydrogen = $\frac{1}{0.10}=10$

For Oxygen = $\frac{0.10}{0.10}=1$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H : O = 9 : 10 : 1

Hence, the empirical formula for the given compound is $C_9H_{10}O$

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 = 268.34 g/mol

Mass of empirical formula = 134 g/mol

Putting values in above equation, we get:

$n=\frac{268.34g/mol}{134g/mol}=2$

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

$C_{(9\times 2)}H_{(10\times 2)}O_{(1\times 2)}=C_{18}H_{20}O_2$

Thus, the molecular formula for the given organic compound is $C_{18}H_{20}O_2$ .

3 0

3 years ago

Consider a transition of the electron in the hydrogen atom from n=5 to n=9. Determine the wavelength of light that is associated

lesantik [10]

Lol i need to answer more and plus n could also = # 4.65

5 0

3 years ago

Identify the characteristics of a good recrystallization solvent. Select one or more: Dissolves a chemical sample well at high t

borishaifa [10]

Answer:

Dissolves a chemical sample well at high temperatures.

Does not dissolve a chemical sample well at low temperatures.

Explanation:

Recrystallization involves the dissolution of the solute in a solvent at high temperature. As the solution cools, it becomes saturated and the solute crystallizes out of the solution.

A good recrystallization solvent must only dissolve the solute at high temperature and must not dissolve it at low temperature. Hence, these are the two conditions required for any good recrystallization solvent.

3 0

2 years ago

A child picks up a tennis ball tied to the end of a rope. He swings the rope around, over his head, in a circle. Once the ball i

kkurt [141]

Answer:

The ball will fly tangential to the original circle

Explanation:

The image here is missing, however we can still answer to the question.

In fact, the circular motion of the ball when it is tied to the rope is a combination of two separate effects:

1- The centripetal force, in the form of the tension in the rop, that pulls the ball at any time towards the centre of the circular path

2- The inertia of the ball, which tends to continue its motion in a straight direction, tangential to the circle and perpendicular to the direction of the centripetal force

When child let the string go, there is no more tension in the string acting on the ball, and therefore, there is no longer a centripetal force.

As a result, number 1) disappears, and therefore there is only the inertia of the ball that will determine its motion: and therefore, the ball will continue its motion straight in a direction tangential to the original circle.

5 0

3 years ago