What is the difference between the orbital periods of Mercury and Earth?Select one:
a. 0.61 years
b. 0.76 years
c. 1.24 years
d. 1.39 years

The number of moles in 987 grams of Ra(OH)2 = 3.8 moles

Calculating number of moles

Ra = 226g

O= 16g

H = 1

Therefore molar mass of Ra(OH)2= 226+ (16+1)×2

= 260g/mol

The molar mass of Ra(OH)2 = 260g/mol

Thus means that 260g of Ra(OH)2 makes up 1 mole

Therefore, 987 g = X moles

Make X moles the subject of formula,

X mole = 987/260

= 3.8 moles

Therefore, the number of moles in 987 grams of Ra(OH)2 = 3.8 moles

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Answer : 3.79 moles are in 987 grams of .

Solution : Given,

Mass of = 987 g

Molar mass of = 260 g/mole

Now we have to calculate the moles of .

Formula used :

Now put all the given values in this formula, we get the moles.

Therefore, 3.79 moles are in 987 grams of .

According to the concept of Avogadro's number, there are 0.0948 moles of silver present in 5.71×10²² atoms of silver.

What is Avogadro's number?

Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.

It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .

According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.

Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number

Therefore, number of moles=number of atoms/Avogadro's number

number of moles=5.71×10²²/6.023×10²³=0.0948

Thus, there are 0.0948 moles in 5.71×10²² atoms of silver.

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N=n×Nav

n=N / Nav

(5.71×10^22) / (6.02×10^23)

n=0.09mol

Light penetration plays a crucial role in the oxygen concentration in the ocean. Light can penetrate up to 50 to 100 meters of the ocean water, leaving high concentration of oxygen at ocean's depth.

The deep oceans are high in the concentration of oxygen. The rates of consumption of oxygen at such depth are low. The phytoplanktons are found in the photic zones of oceans, where these organisms perform photosynthesis. Phytoplanktons are not observed in the deep layers of ocean, therefore, the oxygen consumption will be low. The photosynthetic organisms yield oxygen as a by product, and use up carbon dioxide.

Therefore, the oxygen concentration at deep ocean levels will be higher.

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The invisible electric force field around charged objects depends on the amount of charge, distance involved, and shape of the objects.

What does the formation of charged object depend on ?

The formation of charged matter is depends on the transfer of electrons, either within a material or between two materials. There are three ways this can occur are known as conduction, polarization, and friction.

Charged objects surround themselves with an imperceptible electric force field. The charge, distance, and shape of the items are only a few of the factors that affect strong field.

The electric charge on the particles and the separation between them determine the strength of the electric force. Greater force is produced by larger charges.

Thus, The invisible electric force field around charged objects depends on the amount of charge, distance involved, and shape of the objects.

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Answer:0.0008 mmg

Explanation: