You're home over a holiday and studying for an upcoming electricity test. You read a couple of articles and study some circuit diagrams
before dinner.
You get up to leave your bedroom and join the family. You flip the light
switch to turn out the overhead light as you leave, but notice your
lamp, which is plugged into the wall by your bed, is still on even after
you turn off the light switch. You head to the living room and notice
that the Christmas tree lights are off. You investigate and find that the
lights are plugged in, but there is one broken bulb.What type of circuits are present in your room and the Christmas lights?

a. volume of NaOH needed = 0.07 L or 7.0 mL since mole ratio of CuSO₄ to NaOH is 1 : 2

b. mass of copper (ii) sulfate = 0.32 g

c. Number of moles of NaOH needed, Y = 9.6 * 10⁻¹¹ moles of NaOH

Explanation:

The equation of the reaction is as follows:

CuSO₄ (aq) + 2NaOH(aq) —> Na₂SO₄ (aq) + Cu(OH)₂(s)

Number of moles of CuSO₄ in 3.50 mL of 0.250 M solution

number of moles = molarity * volume

number of moles = 0.250 M * 3.50 mL *  1L/1000 mL = 0.000875 moles

since mole ratio of CuSO₄ to NaOH is 1 : 2,

number of moles of NaOH required = 2 * 0.000875 = 0.00175moles

volume of NaOH required = number of moles/molarity

volume = 0.00175/0.250

volume = 0.07 L or 7.0 mL

b. number of moles = molarity * volume

number of moles = mass/molar mass

molar mass of CuSO₄ = 160 g/mol

number of moles = 0.250 mol/L * 8.00 mL * 1 L/1000 mL

number of moles = 2.00 * 10⁻² moles

2.00 * 10⁻² moles = mass/160 g/mol

mass = 2.00 * 10⁻² moles * 160 g/mol

mass = 0.32 g

c. Mole ratio of CuSO₄ to NaOH is 1 : 2

let number of moles of NaOH be Y

1 mole of CuSO₄/2 moles of NaOH= 4.8 * 10⁻¹¹ moles of CuSO₄/ Y

Y = 2 moles of NaOH * 4.8 * 10⁻¹¹ moles of / 1 moles of CuSO₄

Y = 9.6 * 10⁻¹¹ moles of NaOH