Answer:
A chemical element
Explanation:
A chemical element consists of only one type of atom.
Answer:
the answer you have marked is correct.
C is correct.
The solution for this problem is:
Let x = speed of wind
Speed of plane with the wind = x + 100
Speed of plane against the wind = 100 -x
We will be using the formula for distance which is (Rate)(Time), getting the formula for time would be distance/rate Time to travel 600 miles with the wind = Time to travel 400 miles against the wind 600/(x + 100) = 400/(100 - x)
400(x + 100) = 600(100 - x)
400x + 40000 = 60000 - 600x
1000x = 20000
x = 20000/1000
x = 20 mph
Answer:
An open system
Explanation:
An open system is a system in which both matter and energy are exchanged freely between the system and the surroundings.
An example is a pot of water boiling on the stove. The surroundings (the stove) can supply heat energy to the water and the water can escape into the atmosphere.
A <em>closed system</em> is a system in which energy but not matter is exchanged freely between the system and the surroundings.
An example is a pressure cooker on the stove. The surroundings (the stove) can supply heat energy to the food inside, but no matter can escape through the closed lid.
An <em>isolated system</em> is a system in which neither energy nor matter can be exchanged between the system and the surroundings.
An example is a thermos of hot soup. The cap prevents matter from escaping and the shiny interior reflects heat back into the soup.
Correct answer: "A. Energy from an outside source is continuously being added."
An endothermic reaction is a reaction that is characterised by the system absorbing energy from its surroundings. That energy is usually in heat form. For example, when mixing water<span> with potassium chloride, this reaction will absorb heat and the container will feel cold - endothermic reaction.</span>