A race car driver travelling at 15m*s^-1 accelerates at a constant value for 10.0s. She is now driving at a speed of 35 m*s^-1 What was her acceleration? Give your answer in m*s^-2 to one significant figure . Do not include units with your answer.

The driver speeds up with acceleration a so that

35 m/s = 15 m/s + a (10.0 s)

Solve for a :

20 m/s = a (10.0 s)

a = (20 m/s) / (10.0 s)

a = 2 m/s²

  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

3.2x10^7