Given the speeds of each runner below, determine who runs the fastest.

emily runs 15 feet per second.
jake runs 109 feet in 8 seconds.
stephanie runs 1 mile in 467 seconds.
tony runs 760 feet in 1 minute.

a. emily
b. jake
c. stephanie
d. tony

option A

Explanation:

we will converts all the velocity into SI unit then we can tell who is running fast.

a) Emily runs at 15 ft/s

1 ft/s = 0.3048 m/s

15 ft/s = 4.572 m/s

b) Jack runs at 109 ft in 8 s

1 ft = 0.3048 m

109 ft = 33.22 m

speed = 33.22/8 = 4.152 m/s

c) Stephanie runs 1 mile in 467 seconds

   1 mile = 1609.34 m

  speed = 1609.34/467

      v = 3.45 m/s

d) Tony runs 760 feet in 1 minute.

1 ft = 0.3048 m

760 ft = 231.65 m

speed = 231.65/60 = 3.86 m/s

from the above solution Emily runs fastest.

the correct answer is option A

  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