Answer:
The sign of H is positive, and the products have more potential energy than the reactants.
Explanation:
The options you were given are the following:
- The sign of H is positive, and the products have less potential energy than the reactants.
- The sign of H is positive, and the products have more potential energy than the reactants.
- The sign of H is negative, and the products have less potential energy than the reactants.
- The sign of H is negative, and the products have more potential energy than the reactants.
An endothermic reaction is a chemical reaction that absorbs heat from the surroundings. The absorbed energy provides the activation energy for the reaction to occur.
The sign of H refers to the change in enthalpy. Enthalpy is the thermodynamic property of a system. It is the sum of the internal energy added to the product of the pressure and volume of the system:
If the pressure and volume are constant, the change in enthalpy equals the transferred heat (q). If <em>q</em> is positive, we have an endothermic reaction. The change in enthalpy (the sign of H) in that case always positive, as the change in internal energy is positive (heat is absorbed).
Answer:
C. In 1978, NASA changed the organization of the astronauts; 20 mission specialists and 15 new pilot astronauts were chosen.
Explanation:
B.
In 1978, NASA changed the organization of the astronauts; 20 mission specialists and 15 new pilot astronauts were chosen.
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Answer:
a
Explanation:
the definition of vituperative is abusive
Answer:
A. It identifies the parts of a roller skate, while the text defines the purpose of each part.
Explanation:
Based on the excerpt, there is an explanation given about how to take proper care of a roller skate to make it last longer and be more durable.
The narrator advises on letting the skates air dry after every use, if they have leather boots, cleaning the bearings and oiling them too.
Therefore, the diagram enhances the meaning of the text by identifying the parts of a roller skate, while the text defines the purpose of each part.