Across-country skier can complete a 7.5 km race in 45 min. what is the skier’s average speed? km/h

The average speed of the skier is 10 km/hr.

Explanation:

Average speed is defined as the ratio of total distance traveled to the total time taken.

Mathematically,

We are given:

Total distance traveled = 7.5 km

Total time taken = 45 min =     (Conversion factor: 1 hr = 60 min)

Putting values in above equation, we get:

Hence, the average speed of the skier is 10 km/hr.

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.