The answer is; D
While electromagnetic waves travel at an astounding 3.00 x 10^8 m/s and any delay seems imperceptible in short distances, in long distances, the waves take some time to reach the other end. This is why there is usually a small delay when ground communication tries to reach astronauts in space. Also, remember that when a communication is relayed from the earth, it has to reach the destination and then wait for a response back to earth which covers the same distance or longer/shorter if the target is moving.
The distance to the moon is 384,400 km, therefore multiply this by 2 = 768,800 km
768,800,000m/300,000,000m = 2. 56 seconds
Therefore radio waves sent to the moon from earth will have a minimum 2.5 seconds delay not considering the processing time of this communication by the destination before sending feedback. ‘Over to you’ signals end of a message by the messenger hence allowing the other messenger on the other to respond.
Number of moles = volume / (molar volume)
Molar volume at stp = 22.4 dm^3
Volume = no of moles × molar volume
= 0.987 × 22.4
= 22.1088 dm^3
= 22108.8 cm^3
Hope it helped!
Answer: There are 0.5 grams of barium sulfate are present in 250 of 2.0 M 
solution.
Explanation:
Given: Molarity of solution = 2.0 M
Volume of solution = 250 mL
Convert mL int L as follows.
Molarity is the number of moles of solute present in liter of solution. Hence, molarity of the given solution is as follows.
Thus, we can conclude that there are 0.5 grams of barium sulfate are present in 250 of 2.0 M solution.
