Answer:
A. begin with hydrogen; pair a metal with a hydroxide ion
Explanation:
Acid can be distinguished from base on the basis of formulas in such a way that acid formula start with hydrogen.
For example:
Hydrochloric acid is strong acid. Its formula is HCl.
It start with hydrogen
Sulfuric acid is acid. Its formula is H₂SO₄
it is also start with hydrogen.
Base:
Base is distinguish from acid in such a way that in base formula metal is pair with hydroxide ion.
For example:
Sodium hydroxide is base. Its formula is NaOH.
sodium is metal while OH is hydroxide ion.
Potassium hydroxide is base. its formula is KOH.
potassium is metal and OH is hydroxide ion.
Answer:
B
Explanation:
because mass of an electron is 1/2000.
Answer:
The energy change in a chemical reaction is due to the difference in the amounts of stored chemical energy between the products and the reactants. This stored chemical energy, or heat content, of the system is known as its enthalpy.
Explanation:
Due to the absorption of energy when chemical bonds are broken, and the release of energy when chemical bonds are formed, chemical reactions almost always involve a change in energy between products and reactants. By the Law of Conservation of Energy, however, we know that the total energy of a system must remain unchanged, and that oftentimes a chemical reaction will absorb or release energy in the form of heat, light, or both.
I surmise that the person who asked this question was wondering why water in a room may sometimes be colder than ambient air and by how much.
For water to get cooler than ambient air requires two conditions: exposed water surface or water able to seep through a clay pot, and relatively low ambient humidity level (usually lower than 30% relative humidity). These two conditions combined enable evaporation. Now, evaporation of liquid water into water vapor necessitates input of latent energy (2257 kJ/kg), and this is at the expense of the remaining liquid water. Thus, liquid water in a room can be at a temperature lower than room temperature.
<span>By how much? There is no straight answer to this because the temperature of the remaining liquid water depends on (1) the rate of evaporation, which itself depends on the amount of surface exposure and the room humidity and temperature, (2) the amount of water remaining in the pot, and (3) the rate of reheating of the water by the ambient air. In practice, the water temperature can be lower than room temperature by several degrees Celsius. </span>
What grade is this? I forgot but if u tell me the grade i can prob remember
