The solar system is 25,000 light years from the center of our milky way galaxy. one light year is the distance light travels in one year at a speed of 3.0×108m/s. astronomers have determined that the solar system is orbiting the center of the galaxy at a speed of 230 km/s.
assuming the orbit is circular, what is the period of the solar system's orbit?

t = 2.05 x 10⁸ years

Explanation:

given,

solar system distance from milky way galaxy =  25,000 light years

Speed of light = 3.0×10⁸ m/s

orbiting speed of solar system = 230 Km/s

time period of solar system = ?

1 light year  = 9.461 x 10¹⁵ m

Distance(r) = 25,000 x 9.461 x 10¹⁵ m

              =2.365 x 10²⁰ m

Circumference(r) = 2 π r

                            = 2 x π x 2.365 x 10²⁰

                            = 1.486 x 10²¹ m

distance = speed x time

t = 6.47 x 10¹⁵ sec

t = 2.05 x 10⁸ years

  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

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.