In a movie, the heroine saves the day by cutting a wire before the time runs out on a timer. how did she change the circuit? a. she changed a short circuit to an open circuit. b. she changed an open circuit to a closed circuit. c. she changed a closed circuit to an open circuit. d. she changed a closed circuit to a short circuit.

option c

Explanation:

A circuit contains a conducting wire and a voltage source. Current flows through a closed circuit. A circuit is said to be open if there is break in the circuit that is there is a disconnect such that current does not flow.

When the heroine cuts the wire, she actually breaks the circuit which means that she changed the closed circuit to an open circuit.

option c is correct.

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz