The degree to which a measurement approaches a standard value is ____

Considering that the mantle is 44.8% oxygen and 21.5% silicon by mass, calculate the mole ratio of oxygen atoms to silicon atoms

horrorfan [7]

The mantle has a mass of around $4.278 X 10 ^2^4 kg$ that is around 68.4% of earth's mass.

So to calculate moles we need to first find out the mass of oxygen and silicon present in mantle. It is given that oxygen is 44.8% by mass in mantle and 21.5% by mass in mantle, therefore to calculate its mass, we need to use $\text{mass percentage }=\frac{\text{mole of solute}}{\text{mass of solution}}\times100$

Now, to calculate mass percentage of oxygen

$44.8 =\frac{x}{4.278X10^2^4kg}\times100$

$x= 191.65\times10^2^2kg$

Similarly the mass of silicon can be calculated

$21.5 =\frac{x}{4.278X10^2^4kg}\times100$

$x=91.977\times10^2^2kg$

Now, the moles of any substance is calculated by

$\text{moles}= \frac{\text{given mass}}{\text{molar mass}}$

$\text{moles of oxygen}= \frac{191.65\times10^2^2kg}{2.6566962\times10^-^2^6kg}$

where, mass of oxygen in kilograms is $2.6566962\times10^-^2^6kg$

So, $\text{moles of oxygen}=72.1384\times10^4^8\text{moles of O}$

Similarly $\text{moles of silicon}= \frac{91.977\times10^2^2kg}{4.663\times10^-^2^6kg}$

$\text{moles of silicon}=19.724\times10^4^8\text{moles of Si}$

Now, to calculate mole ratio we need to divide every moles to the lowest calculated mole that is the moles of Si and round it off to the nearest whole number.

$\text{mole ratio of oxygen}= \frac{72.138\times10^4^8kg}{19.724\times10^4^8kg}$

$=3.65\approx 4$

$\text{mole ratio of Silicon}=\frac{19.724\times10^4^8}{19.724\times10^4^8}$

$=1$

$\text{Mole ratio of Oxygen : Mole ratio of Silicon} = 4:1$

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4 years ago

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Oil floats on the surface of water but mercury sinks. why?

andrew-mc [135]

Answer:

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As a whole, plants tend to release more oxygen than carbon dioxide into the environment, but the ratios of gases differ at vario

marshall27 [118]

During the day, due to the existence of sunlight, the procedure of photosynthesis elevations over that of respiration. Photosynthesis uses carbon dioxide to produce carbohydrates removing oxygen as a byproduct. During the night, because there is no sunlight, the rate of photosynthesis decreases. This, therefore, drives the rate of respiration to surpass the speed of photosynthesis. In respiration, oxygen is consumed and carbon dioxide is dismissed.

<h3>What is photosynthesis?</h3>

Photosynthesis is the process by which manufacturers use sunlight, water, and carbon dioxide to produce oxygen and energy in the form of sugar.

The primary position of photosynthesis is to transform solar energy into chemical energy and then reserve that chemical energy for prospective use. For the most part, the planet's living designs are powered by this process.

An illustration of photosynthesis is how plants convert sugar and significance from water, air, and sunlight into energy to grow. Description of photosynthesis is the procedure through which plants use water and carbon dioxide to assemble their food, grow and remove excess oxygen into the air.

To learn more about photosynthesis, refer to:

brainly.com/question/19160081

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1 year ago

Hi, May I have Chem help please? Please Keep the answer as simple as possible because it is a for a bcr.

finlep [7]

Proton:

Mass = 1

Charge = +1

Location = Nucleus

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Mass = 1

Charge = 0

Location = Nucleus

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Mass = 1/2000

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An explosion that releases great amounts of heat is an example of

Damm [24]

<span>An explosion that releases great amounts of heat is an example of an exothermic process. Any reaction that gives off or releases energy as light, electricity, heat, or sound is considered to be exothermic, with "exo" meaning "outside". An explosion is one of the most extreme cases of exothermic reactions.</span>

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The degree to which a measurement approaches a standard value is _____.