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bagirrra123 [75]
3 years ago
13

How many moles of Boron (B) are in 5.03 x 1024 B atoms?

Chemistry
1 answer:
goldfiish [28.3K]3 years ago
3 0

Hey there!:

Number of moles =   ( number of atoms / 6.023*10²³ atoms )

given number of atoms = 5.03*10²⁴

Therefore:

Number of moles B = 5.03*10²⁴ / 6.023*10²³

Number of moles B = 8.35 moles

Hope that helps!


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The goose has a mass of 19.2 lb (pounds) and is flying at 7.10 miles/h (miles per hour). What is the kinetic energy of the goose
nata0808 [166]

Answer:

43.868 J

Explanation:

Kinetic energy of a body is the amount of energy possessed by a moving body. The SI unit of kinetic energy is the joule (kg⋅m²⋅s⁻²).

According to classical mechanics, kinetic energy = 1/2 m·v²

Where, m= mass in kg and v= velocity in m/s

Given: m = 19.2 lb and v = 7.10 miles/h

Since, 1 lb= 0.453592 kg

∴ m = 19.2 lb = 19.2 × 0.453592 kg = 8.709 kg

Also, 1 mi = 1609.34 m and 1 h = 3600 sec

∴ v = 7.10 mi/h = 7.10 × 1609.34 m ÷ 3600 sec = 3.174 m/sec

Therefore, <u>kinetic energy of the goose</u> = 1/2 m·v² = 1/2 × (8.709 kg)× (3.174 m/sec)² = 43.868 J

5 0
3 years ago
You have 50 ml of a complex mixture of weak acids that contains some HF (pKa = 3.18) and some HCN (pKa = 9.21). Which is larger,
bonufazy [111]

Answer:

\frac{[F^{-}]}{[HF]} is larger

Explanation:

pK_{a}=-logK_{a} , where K_{a} is the acid dissociation constant.

For a monoprotic acid e.g. HA, K_{a}=\frac{[H^{+}][A^{-}]}{[HA]} and \frac{[A^{-}]}{[HA]}=\frac{K_{a}}{[H^{+}]}

So, clearly, higher the K_{a} value , lower will the the pK_{a}

In this mixture, at equilibrium, [H^{+}] will be constant.

K_{a} of HF is grater than K_{a} of HCN

Hence, (\frac{F^{-}}{[HF]}=\frac{K_{a}(HF)}{[H^{+}]})>(\frac{CN^{-}}{[HCN]}=\frac{K_{a}(HCN)}{[H^{+}]})

So, \frac{[F^{-}]}{[HF]} is larger

5 0
3 years ago
Ứng dụng điều chế của lưu huỳnh thành oxit axit ?
Juli2301 [7.4K]

that's your work bro do by your own

6 0
3 years ago
The molar mass of an unknown gas was measured by an effusion experiment. It was found that it took 60 s for the gas to effuse, w
Marizza181 [45]

Answer:

The molar mass of the gas is 44 g/mol

Explanation:

It is possible to solve this problem using Graham's law that says: Rates of effusion are inversely dependent on the square of the mass of each gas. That is:

\frac{r_1}{r_2} =\frac{\sqrt{M_2} }{\sqrt{M_1} }

If rate of effusion of nitrogen is Xdistance / 48s and for the unknown gas is X distance / 60s and mass of nitrogen gas is 28g/mol (N₂):

\frac{X/48s}{X/60s} =\frac{\sqrt{M_2} }{\sqrt{28g/mol} }

6,61 = √M₂

44g/mol = M₂

<em>The molar mass of the gas is 44 g/mol</em>

<em></em>

I hope it helps!

4 0
3 years ago
How do you get hyphen notations?
laiz [17]

Answer:

In hyphen notation, the mass number is written after the name of the element. For example, in isotopic notation, the isotope of carbon that has a mass number of twelve would be represented as 12C . In hyphen notation, it would be written as carbon-12.

Explanation:

lol just took the question and looked it up online this was the first thing that i saw if its not correct im sorry

6 0
3 years ago
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