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Ostrovityanka [42]
3 years ago
7

What is the second most abundant element in stars? A. helium B. iron C. hydrogen D. oxygen

Chemistry
1 answer:
devlian [24]3 years ago
8 0
<span>The </span>abundance of a chemical element<span> is a measure of the </span>occurrence<span> of the </span>element<span> relative to all other elements in a given environment. Abundance is measured in one of three ways: by the </span>mass-fraction<span> (the same as weight fraction); by the </span>mole-fraction<span> (fraction of atoms by numerical count, or sometimes fraction of molecules in gases); or by the </span>volume-fraction<span>. Volume-fraction is a common abundance measure in mixed gases such as planetary atmospheres, and is similar in value to molecular mole-fraction for gas mixtures at relatively low densities and pressures, and </span>ideal gas<span> mixtures. Most abundance values in this article are given as mass-fractions.

</span>
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What happens to the volume of a gas in a closed container if the temperature increases, but the pressure remains the same? Why?
labwork [276]

Answer:

Volume will goes to increase.

Explanation:

The given problem will be solve through the Charles Law.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume  

T₂ = Final temperature

So when the temperature goes to increase the volume of gas also increase. Higher temperature increase the kinetic energy and molecules move randomly every where in given space so volume increase.

Now we will put the suppose values in formula.

V₁/T₁ = V₂/T₂

V₂ = V₁T₂/T₁  

V₂ = 4.5 L × 348 K / 298 k

V₂ = 1566 L.K / 298 K

V₂ = 5.3 L

Hence prove that volume increase by increasing the temperature.

3 0
3 years ago
Inside a flashbulb, oxygen surrounds a thin coil of magnesium. When the flashbulb is set off, a chemical reaction takes place in
hoa [83]

Answer:

Oxygen and magnesium come together in a chemical reaction to form this compound. After it burns, it forms a white powder of the magnesium oxide. Magnesium gives up two electrons to oxygen atoms to form this powdery product. This is an exothermic reaction.

6 0
2 years ago
If log x = -0.761. What does x equal
kvasek [131]
The logarithm from my understanding can never be negative. You can check this on a calculator. You may have a negative if it is shown as -(log x).
4 0
3 years ago
A student uses a calorimeter to determine the enthalpy of dissolving for ammonium nitrate. The student fills a calorimeter with
ale4655 [162]
Enthalpy change during the dissolution process = m c ΔT,

here, m = total mass = 475 + 125 = 600 g
c = <span>specific heat of water = 4.18 J/g °C
</span>ΔT = 7.8 - 24 = -16.2 oc (negative sign indicates that temp. has decreases)
<span>
Therefore, </span>Enthalpy change during the dissolution = 600 x 4.18 X (-16.2)
                                                                                 = -40630 kJ
(Negative sign indicates that process is endothermic in nature i.e. heat is taken by the system)

Thus, <span>enthalpy of dissolving of the ammonium nitrate is -40630 J/g</span>

7 0
3 years ago
How does salt dissolve in water?
iogann1982 [59]
Water<span> can </span>dissolve salt<span> because the positive part of</span>water<span> molecules attracts the negative chloride ions and the negative part of </span>water<span> molecules attracts the positive sodium ions</span>
7 0
2 years ago
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