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3 years ago

_Li + __F2 → _LIF How do I balance this?

Chemistry

1 answer:

Semmy [17]3 years ago

5 0

Answer:

2Li + F₂ → 2LiF

Explanation:

The reaction expression is given as:

Li + F₂ → LiF

We are to balance the expression. In that case, the number of atoms on both sides of the expression must be the same.

Let use a mathematical approach to solve this problem;

Assign variables a,b and c as the coefficients that will balance the expression:

aLi + bF₂ → cLiF

Conserving Li: a = c

F: 2b = c

let a = 1, c = 1 and b = $\frac{1}{2}$

Multiply through by 2;

a = 2, b = 1 and c = 2

2Li + F₂ → 2LiF

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Convert the shorthand structure of tyrosine to a complete structure with all atoms and lone pairs drawn in. Tyrosine is one of t

Vikentia [17]

Answer:

Explanation:

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4 years ago

How many electrons are in an element if the atomic number is 11?

tatuchka [14]

The answer is sodium
Sodium has 11 protons (atomic number is 11) and has one valence electron. As the Bohr model diagram below shows, Sodium has 11 protons and 12 neutrons in the nucleus to make the mass number 23. The 11 electrons necessary to make Sodium neutral (protons = electrons) are arranged in a pattern of 2-8-1.

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3 years ago

The density of water is 1.00 g/mL. If your swimming pool holds 208,000 gallons of water, what is the weight of the water in a fi

Natasha2012 [34]

Answer:

12.455≈12.5 tons

Explanation:

1 US gallon of water (gal) = 8.35 pounds of water (lb wt.)

so we divide 208,000 by 8.35 to covert to pounds

then divide the pounds by 2000 to convert to tons.

8 0

3 years ago

Calculate the mass defect for the formation of phosphorus-31. The mass of a phosphorus-31 nucleus is 30.973765 amu. The masses o

Nata [24]

Answer: The mass defect for the formation of phosphorus-31 is 0.27399

Explanation:

Mass defect is defined as the difference in the mass of an isotope and its mass number.

The equation used to calculate mass defect follows:

$\Delta m=[(n_p\times m_p)+(n_n\times m_n)]-M$

where,

$n_p$ = number of protons

$m_p$ = mass of one proton

$n_n$ = number of neutrons

$m_n$ = mass of one neutron

M = mass number of element

We are given:

An isotope of phosphorus which is $_{15}^{31}\textrm{P}$

Number of protons = atomic number = 15

Number of neutrons = Mass number - atomic number = 31 - 15 = 16

Mass of proton = 1.00728 amu

Mass of neutron = 1.00866 amu

Mass number of phosphorus = 30.973765 amu

Putting values in above equation, we get:

$\Delta m=[(15\times 1.00728)+(16\times 1.00866)]-30.973765\\\\\Delta m=0.27399$

Hence, the mass defect for the formation of phosphorus-31 is 0.27399

8 0

3 years ago

Determine the energy of the electron in the 1s orbital of a helium ion (He+ )

Luda [366]

He Rydberg formula can be extended for use with any hydrogen-like chemical elements.
1/ λ = R*Z^2 [ 1/n1^2 - 1/n2^2] 
where 
λ is the wavelength of the light emitted in vacuum; 
R is the Rydberg constant for this element; R 1.09737x 10^7 m-1 
Z is the atomic number, for He, Z =2; 
n1 and n2 are integers such that n1 < n2 
The energy of a He+ 1s orbital is the opposite to the energy needed to ionize the electron that is 
taking it from n = 1 (1/n1^2 =1) to n2 = ∞ (1/n2^2 = 0) 
.: 1/ λ = R*Z^2 = 1.09737x 10^7*(2)^2 
λ = 2.278*10^-8 m 
E = h*c/λ 
Planck constant h = 6.626x10^-34 J s 
c = speed of light = 2.998 x 10^8 m s-1 
E = (6.626x10^-34*2.998 x 10^8)/(2.278*10^-8) = 8.72*10^-18 J ion-1 
Can convert this value to kJ mol-1: 
(8.72*10^-18*6.022 x 10^23)/1*10^3 = 5251 kJ mol-1 
Lit value: RP’s secret book: 5240.4 kJ mol-1 (difference is due to a small change in R going from H to He+) 
So energy of the 1s e- in He+ = -5251 kJ mol-1

6 0

3 years ago