There are two naturally occurring isotopes of gallium: mass of Ga-69 isotope is 68.9256 amu and its percentage abundance is 60.11%, let the mass of other isotope that is Ga-71 be X, the percentage abundance can be calculated as:

%Ga-71=100-60.11=39.89%

Atomic mass of an element is calculated by taking sum of atomic masses of its isotopes multiplied by their percentage abundance.

Thus, in this case:

Atomic mass= m(Ga-69)×%(Ga-69)+X×%(Ga-71)

From the periodic table, atomic mass of Ga is 69.723 amu.

Putting the values,

$69.723 amu=(68.9256 amu)(\frac{60.11}{100})+X(\frac{39.89}{100})$

Thus,

$69.723 amu=41.4312 amu+X(\frac{39.89}{100})$

Rearranging,

$X=\frac{69.723 amu-41.4312 amu}{0.3989}=70.9246 amu$

Therefore, mass of Ga-71 isotope is 70.9246 amu.

7 0

2 years ago

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A 33.69 g sample of a substance is initially at 29.4 °c. after absorbing 1623 j of heat, the temperature of the substance is 110

Sliva [168]

Q= mcΔT
1623 = 33.69g x c x (110.8 - 29.4)
1623 = 2742.366 g•°C x c
c = 0.59j/g•°C

4 0

3 years ago

A. 1720 kJ<br> B. 125.6 kJ<br> C. 3440 kJ<br> D. 4730 kJ

Feliz [49]

Answer:

Q = 3440Kj

Explanation:

Given data:

Mass of gold = 2kg

Latent heat of vaporization = 1720 Kj/Kg

Energy required to vaporize 2kg gold = ?

Solution:

Equation

Q= mLvap

It is given that heat required to vaporize the one kilogram gold is 1720 Kj thus, for 2 kg

by putting values,

Q= 2kg × 1720 Kj/Kg

Q = 3440Kj

7 0

2 years ago