16 William is sliding down a plastic slide on a playground. After he slides down the ground, he feels a small electric shock when he touches a piece of metal. What has been built up on his body
that causes the shock?
A atoms
B electrons
C. neutrons
D. protons

B) Electrons

Explanation:

When William slides down the slide, the rubbing action between William and the slide causes electrons to be transferred to William and stored as a negative charge.

When he touches a piece of metal, the negative charge (i.e the build up of excess electrons), is released (discharged) into the metal causing what we know as a static shock.

  the grams     of oxygen gas   that can be produced     is 20.6   grams of o₂

calculation

2liclo₃ →   2 licl + 3 o₂

step 1:   find the moles of liclo₃

moles = mass÷ molar mass

from periodic table the molar mass of liclo₃ =6.9 +35.5   +(16 x3) =90.4 g/mol

moles=38.7 g÷90.4 g/mol=0.4281   moles

step 2:   use the   mole ratio   to calculate the moles of o2

from equation above, liclo₃: o₂   is 2: 3  

therefore the moles of   o₂=0.4281 moles x3/2 =0.6422   moles

step 3: find mass   of o₂

mass= moles x molar mass

from periodic table the   molar mass of   o₂ = 16 x2= 32 g/mol

mass=0.6422   moles   x   32 g/mol = 20.6 grams of o₂