Ethanol has the chemical formula C2H5OH. Write and balance the chemical reaction for the combustion of ethanol

The molecular formula for caffeine is C8H10N4O2. Which of the following elements is not found in caffeine?

ANTONII [103]

The correct answer is:

b: Heluim

Explanation:

The caffeine contains: carbon , nitrogen , oxygen , hydrogen.

Caffeine is a primary nervous system energizer of the methylxanthine class. It is the world's most universally consumed psychoactive drug. Unlike many other psychoactive elements, it is fair and unlimited in nearly all parts of the world. Caffeine can be arranged as an alkaloid, a term used for substances originated as end results of nitrogen metabolism in some plants.

5 0

3 years ago

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What is the composition, in atom percent, of an alloy that consists of a) 5.5 wt% Pb and b) 94.5 wt% of Sn? Assume that the atom

Anastaziya [24]

Answer : The percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.

Explanation :

First we have to calculate the number of atoms in 5.5 wt% Pb and 94.5 wt% of Sn.

As, 207.2 g of lead contains $6.022\times 10^{23}$ atoms

So, 5.5 g of lead contains $\frac{5.5}{207.2}\times 6.022\times 10^{23}=1.59\times 10^{22}$ atoms

and,

As, 118.71 g of lead contains $6.022\times 10^{23}$ atoms

So, 94.5 g of lead contains $\frac{94.5}{118.71}\times 6.022\times 10^{23}=4.79\times 10^{23}$ atoms

Now we have to calculate the percent composition of Pb and Sn in atom.

$\% \text{Composition of Pb}=\frac{\text{Atoms of Pb}}{\text{Atoms of Pb}+\text{Atoms of Sn}}\times 100$

$\% \text{Composition of Pb}=\frac{1.59\times 10^{22}}{(1.59\times 10^{22})+(4.79\times 10^{23})}\times 100=3.21\%$

and,

$\% \text{Composition of Sn}=\frac{\text{Atoms of Sn}}{\text{Atoms of Pb}+\text{Atoms of Sn}}\times 100$

$\% \text{Composition of Sn}=\frac{4.79\times 10^{23}}{(1.59\times 10^{22})+(4.79\times 10^{23})}\times 100=96.8\%$

Thus, the percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.

6 0

3 years ago

43 milliliters of water weighs 43 g. what is the density of the water?

Anastaziya [24]

Answer:

$\rho =1g/mL$

Explanation:

Hello,

In this case, since the density is defined as the ratio between the mass and the volume as shown below:

$\rho =\frac{m}{V}$

We can compute the density of water for the given 43 g that occupy the volume of 43 mL:

$\rho =\frac{43g}{43mL}=1g/mL$

Regards.

4 0

3 years ago

A burning splint will burn more vigorously in pure oxygen than in air because ________. a burning splint will burn more vigorous

GrogVix [38]

A burning splint will burn more vigorously in pure oxygen than in air because <span>oxygen is a reactant in combustion and concentration of oxygen is higher in pure oxygen than is in air.
Oxygen concentration in air is approximately 20%, the rest of are nitrogen, carbon dioxide and other gases. Oxygen is oxidazing reactant, that means oxygen give electrons in chemical reactions.
</span>

6 0

3 years ago

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What is the most abundant greenhouse gas released through human activities? a. methane b. nitrous oxide c. carbon dioxide d. sul

777dan777 [17]

Answer:

C. Carbon dioxide. (C02.)

Explanation:

Hope this helps. :)

6 0

2 years ago

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Ethanol has the chemical formula C2H5OH. Write and balance the chemical reaction for the combustion of ethanol​

Ethanol has the chemical formula C2H5OH. Write and balance the chemical reaction for the combustion of ethanol