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3 years ago

Hurry up as fast as possible Ill mark you brainlist

Chemistry

1 answer:

Vika [28.1K]3 years ago

6 0

It took 380,000 years for electrons to be trapped in orbits around nuclei, forming the first atoms.

These were mainly helium and hydrogen, which are still by far the most abundant elements in the universe. Present observations suggest that the first stars formed from clouds of gas around 150–200 million years after the Big Bang. Heavier atoms such as carbon, oxygen and iron, have since been continuously produced in the hearts of stars and catapulted throughout the universe in spectacular stellar explosions called supernovae.

You might be interested in

Is the following nuclear equation balanced?<br> 237 Np - He+233 AM

Flura [38]

Answer:

Yes

Explanation:

Np²³⁷ → He⁴ + Am²³³

The given nuclear equation is balanced. Np²³⁷ undergoes alpha decay and produce alpha particle and Am²³³.

Properties of alpha radiation:

Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number 4 less than and atomic number 2 less than the starting atom.

Alpha radiations can travel in a short distance.

These radiations can not penetrate into the skin or clothes.

These radiations can be harmful for the human if these are inhaled.

These radiations can be stopped by a piece of paper.

₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ + energy

6 0

3 years ago

7. what is the density of an object having a mass of 8.0 g and a volume of 25 cm^3? a) 0.32g/cm^3 b) 2.0 g/cm^3 c) 3.1 g/cm^3 d)

natulia [17]

D = m / V

D = 8.0 g / 25 cm³

D = 0.32 g/cm³

Answer A

6 0

3 years ago

ASAP PLS

AveGali [126]

Answer:

think I did this before and its V

8 0

3 years ago

A 6.165 gram sample of an organic compound containing C, H and O is analyzed by combustion analysis and 10.27 grams of CO2 and 3

e-lub [12.9K]

Answer:

Explanation:

mass of carbon in 10.27 g of CO₂ = 12 x 10.27 / 44 = 2.80 g

mass of hydrogen ( H ) in 3.363 g of H₂O = 2 x 3.363 / 18

= .373 g

These masses would have come from the sample of 6.165 g .

Rest of 6.165 g of sample is oxygen .

So oxygen in the sample = 6.165 - ( 2.8 + .373 ) = 2.992 g

Ratio of C , H , O in the sample

2.8 : .373 : 2.992

C: H : O : : 2.8 : .373 : 2.992

Ratio of moles

C: H : O : : 2.8/12 : .373/1 : 2.992 / 16

C: H : O : : .2333 : .373 : .187

C: H : O : : .2333/.187 : .373/.187 : .187/.187

C: H : O : : 1.247 : 1.99 : 1

C: H : O : : 5 : 8 : 4 ( after multiplying by 4 )

Hence empirical formula

C₅H₈O₄

Molecular formula ( C₅H₈O₄ )n

n ( 5 x 12 + 8 x 1 + 4 x 16 ) = 132

n x ( 60 + 8 + 64 ) = 132

n = 1

Molecular formula = C₅H₈O₄.

3 0

3 years ago

A sample of gas occupies a volume of 445 mL at a temperature of 274 K. At what temperature will this sample of gas occupy a volu

Ksenya-84 [330]

V1 = 445ml V2 = 499ml
T1 = 274 K T2 = ?

By Charles Law,
V1/T1 = V2/T2
445/274 = 499/T2
By solving we get,
T2 = 307.25 K

4 0

3 years ago