Which of the following is an example of a velocity? o a. 12 m/s o b. 45 km/hr south o c. 55 km/hr d. -5 m/s2 east

B. 45 km/hr south

Explanation:

Velocity is a vector quantity which consists of:

- A magnitude, given by the ratio between displacement and time taken for the motion

- A direction, which corresponds to the direction of the displacement

Let's analyze now each option:

A. 12 m/s --> this is not a velocity: this is a speed, because it does not specify the direction, so it is only a scalar quantity

45 km/hr south --> this is a velocity, because it specificies both magnitude (45 km/h) and direction (south)

C. 55 km/hr  --> again ,this is not a velocity, but it is a speed, because it does not specify the direction, so it is only a scalar quantity

D. -5 m/s2 east --> this is not a velocity, but it is an acceleration, since the units of measurement are the ones of acceleration (m/s^2, while for the velocity should be m/s or km/h)

answer; (d) spontaneous processes are characterized by the overall conversion of order to disorder;

  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