What title would be given to the vertical axis on the graph for the boiling water and salt experiment?

Q1. Calculate the amount of copper produced in 1.0 hour when aqueous CuBr2 solution was electrolyzed by using a current of 4.50

OLga [1]

Answer:

$\boxed{\text{Q1. 3.6 g; Q2. 0.2 A}}$

Explanation:

Q1. Mass of Cu

(a) Write the equation for the half-reaction.

Cu²⁺ + 2e⁻ ⟶ Cu

The number of electrons transferred (z) is 2 mol per mole of Cu.

(b) Calculate the number of coulombs

q = It

$\text{t} = \text{1.0 h} \times \dfrac{\text{3600 s}}{\text{1 h}} = \text{3600 s}\\\\q = \text{3 C/s} \times \text{ 3600 s} = \textbf{10 800 C}$

(c) Mass of Cu

We can summarize Faraday's laws of electrolysis as

$\begin{array}{rcl}m &=& \dfrac{qM}{zF}\\\\& = &\dfrac{10 800 \times 63.55}{2 \times 96 485}\\\\& = & \textbf{3.6 g}\\\end{array}\\\text{The mass of Cu produced is $\boxed{\textbf{3.6 g}}$}$

Note: The answer can have only two significant figures because that is all you gave for the time.

Q2. Current used

(a) Write the equation for the half-reaction.

Ag⁺ + e⁻ ⟶ Ag

The number of electrons transferred (z) is 1 mol per mole of Ag.

(a) Calculate q

$\begin{array}{rcl}m &=& \dfrac{qM}{zF}\\\\2.00& = &\dfrac{q \times 107.87}{1 \times 96 485}\\\\q &=& \dfrac{2.00 \times 96485}{107.87}\\\\& = & \textbf{1789 C}\\\end{array}$

(b) Calculate the current

t = 3 h = 3 × 3600 s = 10 800 s

$\begin{array}{rcl}q&=& It\\1789 & = & I \times 10800\\I & = & \dfrac{1789}{10800}\\\\& = & \textbf{0.2 A}\\\end{array}\\\text{The current used was $\large \boxed{\textbf{0.2 A}}$}$

Note: The answer can have only one significant figure because that is all you gave for the time.

4 0

2 years ago

(b) The mass of a single molybdenum atom is 1.59×10-22 g. Suppose enough Mo atoms were lined up like beads on a string to span a

serious [3.7K]

Answer:N=1151724138 atoms

Explanation:The atomic radius of molybdenum atom is 145 picometers so lining up molybdenum atoms is like lining up the beads of radius 145 picometers

so one bead would cover the length of 145*2=290 picometers

hence the atom's diameter =D=290 picometers

D=290 *10^(-12)

$D=290/1000000000000$

also

Distance span= 33.4 cm

Distance span= 0.334m

As the Distance span adds up with no of atoms the resulting formula is

Distance span by atoms= No of atoms * atom's diameter

so

$N=\frac{Distance Spaned}{Atom's Diameter } \\N=0.334/(0.000000000290)\\N=1151724138 atoms$

4 0

2 years ago

The sodium isotope with 13 neutrons. Express your answer as an isotope

wariber [46]

Answer:

$\large\boxed{\large\boxed{^{24}_{11}Na}}$

Explanation:

The question is asking to write the <em>isotopic symbol </em>of the form $^A_ZX$ for the <em>sodium isotope with 13 neutrons</em>.

In general, the isotopic symbol in the given form shows:

The element's chemical symbol: X

A: mass number of the isotope, written as a superscript to the left of the element's simbol, and

A = number of protons + number of neutrons

Z: atomic number of the isotope, written as a subscript to the left of the elements's symbol,

Z = number of protons

The atomic symbol of sodium is Na.

The atomic number, or number of protons, is the same for every isotope of the element, and you can find it in any periodic table. Tha atomic number of sodium is 11. Thus: