Answer:
There are quite a number of units to measure speed and depending on how fast an object is going, some are more preferred than others.
The units are:
- Metres per second - this is on of the most common units and is regularly used by runners.
- Kilometres per hour - used by cars, buses and generally objects that move adequately fast.
- Miles per hour - this is a substitute to kilometers per hour for countries using the imperial system or miles instead of kilometers.
- Knots - Represent nautical miles and are a unit of speed mostly used to measure wind and water speed.
- Feet per second - Not as popular but used in countries that don't regularly use metres.
- Mach number - for really fast objects going faster than sound.
Answer:
A. Bubbles formed
Explanation:
When a student added a piece of limestone to a solution of hydrochloric acid, bubbles are formed.
The bubbles are as a result of the CO2 gas that is formed.
Below is the reaction:
CaCO3+2HCl → CO2+H2O + Ca++ + 2Cl-
From the left hand side, we can see that the reaction is with limestone and hydrochloric acid. Their reaction forms carbon dioxide gas (CO2), water (H2O), dissolved calcium (Ca++) and dissolved chlorine (Cl-) on the right hand side.
With due observation, bubbles will be seen evolving from the reaction. These bubbles formed is the carbon dioxide gas which reveals that a reaction is taking place.
It is a simple sentence. This is the group it belongs to.
I believe its five -The Romance Stage
The Power Struggle Stage
The Stability Stage
The Commitment Stage
The Co-Creation or Bliss