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3 years ago

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An isotope has three forms. 30% have a mass of 15 amu, 20% have a mass of 16 amu and 50% have a mass of 17 amu. What is the aver

age atomic
mass of this element?
a. 15.8 amu
b. 16.0 amu
c. 16.2 amu
d. 16.4 amu

1 answer:

murzikaleks [220]3 years ago

3 0

Answer:

Explanation:

a

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My swimming pool is rectangular (16 feet by 34 feet) and has a depth of 6 feet. Lets imagine that my pool water is full to the t

Reil [10]

Answer:

Number of moles of photons required = 5.04 × 10⁴ moles

Explanation:

The energy of a photon can be calculated from Planck's equation E = hc/λ

Where h = 6.63 × 10-³⁴ Js and c, the velocity of light = 3.0 × 10⁸ m/s

Energy of one mole of photons = N₀ × hc/λ

wavelength of photon, λ = 520 nm = 5.20 × 10-⁷ m

Energy of one mole of photons = 6.02 × 10²³ × 6.63 × 10−³⁴ × 3 × 10⁸/5.20 × 10-⁷

Energy of one mole of photons = 2.30 × 10⁵ J/mol

Energy required to raise the temperature of a given mass of a substance, E = mcΔT

Where m is mass of substance, c is specific heat capacity, ΔT is temperature difference

Mass ofnwternin the pool = volume × density

Volume of water = Volume of swimming pool

Volume of water = 16 × 34 × 6 ft³ = 3264 ft³

1 ft³ = 28316.8 cm³; 3264 ft³ = 28316.8 × 3264 = 92426035.2 cm³

Density of water = 1 g/cm³

Mass of water = 92426035.2 cm³ × 1 g/cm³ = 92426035.2g

ΔT = 80°C - 50°C = 30°C, c = 4.18 J/g/K

Energy required to raise 92426035.2 g water by 30° C = 92426035.2 × 4.18 × 30

Energy required = 1.16 × 10¹⁰ J

Hence, number of moles of photons required = 1.16 × 10¹⁰ J/2.30 × 10⁵ J/mol

Number of moles of photons required = 5.04 × 10⁴ moles

5 0

3 years ago

Ideal gas (n 2.388 moles) is heated at constant volume from T1 299.5 K to final temperature T2 369.5 K. Calculate the work and h

bija089 [108]

Answer : The work, heat during the process and the change of entropy of the gas are, 0 J, 3333.003 J and -10 J respectively.

Explanation :

(a) At constant volume condition the entropy change of the gas is:

$\Delta S=-n\times C_v\ln \frac{T_2}{T_1}$

We know that,

The relation between the $C_p\text{ and }C_v$ for an ideal gas are :

$C_p-C_v=R$

As we are given :

$C_p=28.253J/K.mole$

$28.253J/K.mole-C_v=8.314J/K.mole$

$C_v=19.939J/K.mole$

Now we have to calculate the entropy change of the gas.

$\Delta S=-n\times C_v\ln \frac{T_2}{T_1}$

$\Delta S=-2.388\times 19.939J/K.mole\ln \frac{369.5K}{299.5K}=-10J$

(b) As we know that, the work done for isochoric (constant volume) is equal to zero. $(w=-pdV)$

(C) Heat during the process will be,

$q=n\times C_v\times (T_2-T_1)=2.388mole\times 19.939J/K.mole\times (369.5-299.5)K= 3333.003J$

Therefore, the work, heat during the process and the change of entropy of the gas are, 0 J, 3333.003 J and -10 J respectively.

7 0

3 years ago

How many molecules Of H20 are<br> equivalent to 97.2 g H20?<br> (H = 1.008 g/mol, O = 16.00 g/mol)

AleksandrR [38]

Answer:

m(H₂O) = 97,2 g.n(H₂O) = m(H₂O) ÷ M(H₂O).n(H₂O) = 97,2 g ÷ 18

Explanation:

8 0

2 years ago

Which element has the greatest density at STP?

son4ous [18]

Answer: Option (4) is the correct answer.

Explanation:

It is known that density is mass divided by volume.

Mathematically, Density = $\frac{mass}{volume}$

Since, density is directly proportional to mass. So, more is the mass of an element more will be its density.

Mass of magnesium is 24.305 g/mol.

Mass of barium is 137.327 g/mol.

Mass of beryllium is 9.012 g/mol

Mass of radium is 226 g/mol.

Hence, radium has more mass therefore it will have the greatest density at STP.

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3 years ago

Homogenized milk is a colloid. It has been treated to prevent its different components from separating when it stands. When non-

frez [133]

Answer:

Heterogeneous mixture

Explanation:

A homogeneous mixture is defined as a mixture in which the constituents of the mixture are uniformly distributed. A typical example of a homogeneous mixture is when a salt is dissolved in water.

A heterogeneous mixture refers to a kind of mixture whereby the composition of the mixture is not uniform. A typically example of a heterogeneous mixture is non-homogenized milk.

Since non-homogenized milk is not homogeneous, the cream rises to the top and separates from the rest of the mixture because the emulsion has not been stabilized. However, homogenized milk is just milk whose emulsion has been stabilized the cream does not separate when left to stand.

7 0

3 years ago