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3 years ago

How does helium form (5-8) sentences

1 answer:

7 0

On Earth it is relatively rare—5.2 ppm by volume in the atmosphere. Most terrestrial helium<span> present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium, although there are other examples), as the alpha particles emitted by such decays consist of </span>helium<span>-4 nuclei.</span>

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Which of the following is a precipitation reaction?

erik [133]

Answer:

The precipitated are option a and d.

Explanation:

2 LiI(aq) +Hg2(NO3)2(aq) → Hg2I2(s) ↓ + 2 LiNO3(aq)

Cation Hg2+ 2 in the presence of iodide, a precipitated is formed.

Zn(s) + 2AgNO3(aq) → 2 Ag(s) ↓ +Zn(NO3)2(aq)

Zinc starts to get rid, and some white particles also stick to it. Afterwards the solution becomes cloudy and a precipitate appears, which is the solid silver

3 0

3 years ago

Which of the following is the balanced chemical equation for the combustion of methane, CH4?

ki77a [65]

C I pretty sure it's C but I could be wrong

5 0

3 years ago

Molten gallium reacts with arsenic to form the semiconductor, gallium arsenide, GaAs, used in light-emitting diodes and solar ce

Vsevolod [243]

Answer:

a) 1.2g of arsenic b) 0.64g of arsenic c) 3.481g of gallium d) 3.806g of gallium e) 2.61g arsenic

Explanation:

The balanced equation is:

Ga + As = GaAs, 1:1 mole ratio

a) mass (gallium)/ molar mass of Ga = 4/ 69.723 = 0.0574mol

Mass (arsenic)/ molar mass of As = 5.5/74.9216 = 0.0734, subtracting the moles from each other (knowing already that the ratio is 1:1), arsenic is in excess by 1.2g

b) repeating the procedure (changing the values)

It will be 0.0574 to 0.06593

Arsenic is in excess by 0.00854

0.00854* mass of arsenic (such must be done for the first remaining mole) = 0.64g

c) the mole ratio is 0.0574: 0.00747

Gallium is in excess by 0.05

Mass of excess gallium = 0.05* 69.723 = 3.481g

d) using the mass given, the new ratio is

0.128: 0.0734

Gallium is in excess by 0.054mol

Mass of excess gallium = 0.054*69.723 = 3.806g

e) using the mass again, the new ratio is 0.0574: 0.02,

Gallium is in excess by 0.0374*69.723 = 2.61g

7 0

4 years ago

Compare the costs of using renewable resources to the costs of using nonrenewable resources.

Vitek1552 [10]

Answer:

Sample response:

The costs of using both renewable and nonrenewable resources depend on the extent of the use. If renewable resources are managed wisely, the use of the resource will not exceed the rate at which it is replenished. In this instance the cost of using renewable resources can be minimized, if not entirely eliminated. The cost of using nonrenewable resources is harder to minimize because nonrenewable resources cannot be replenished at the rate at which they are used. The environmental impact of using nonrenewable resources such as fossil fuels is greater than just the loss of the resource itself. Other impacts such as acid rain, global warming, and atmospheric pollution can result from the use of nonrenewable resources.

Explanation:

2021 edge

have a nice day

8 0

3 years ago

Read 2 more answers

You have a solution with an unknown concentration of hcl, in order to determine the concentration of hcl you titrate 35.00ml of

slava [35]

Answer:-

0.648 M

Explanation:-

Volume of Ba(OH)2= 34.63ml/1000=0.03463 litre

Number of moles of Ba(OH)2 = 0.3275 M x 0.03463 litre

= 0.01134 moles

Since Ba(OH)2 has 2 OH in its formula,

Number of moles of OH- = 2 x 0.01134=0.02268 moles.

Volume of HCl= 35ml/1000 = 0.035 litre

At the end point number of moles of H+ = number of moles of OH-.

Number of moles of HCL= Concentration of HCl x Volume of HCl

∴ Concentration of HCl = 0.02268 moles/ 0.035 litre

= 0.648 moles/ litre

= 0.648 M

3 0

3 years ago