Answer: A. Endothermic
Explanation:
In an endothermic reaction, heat is sucked in from the surrounding area by the reactants so that they may use it to react and form new products. This will therefore reduce the temperature in the said surrounding by the amount that the reaction needed.
This is what ice does when it melts. It sucks in the heat surrounding the area and then melts but leaves the area colder. For instance, putting ice in water ensures that the ice melts but because it sucked in the heat from the water to do so, the water gets colder as a result.
Answer: caffeine is a compound.
Explanation:
1) As stated c<span>affeine contains hydrogen, carbon, nitrogen, and oxygen atoms in a fixed ratio.
2) The definition of compound is a pure substance formed by chemical bonding of two or more fifferent elements. That means a defined ratio of the elements in the compound, which conferes uniform and equal properties to every part of the compound.
Some examples of compounds are salt (NaCl), water (H2O), vinegard (CH3 COOH).
A mixture combines several elements or compounds, not bonded by chemical bonds but mixed in ratios which may vary.
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Answer: Number of moles of NaCl per liter of solution
Explanation: Molarity can be defined as the number of moles
of solute per liter of solution.
Therefore the molarity of an aqueous solution of NaCl is thus defined as the number of moles of NaCl per liter of solution.
Adding a volatile liquid in the Erlenmeyer flask will increase the total pressure inside the flask. This is because inside the flask, there will be two components: the vapor and the liquid. Each of which will exhibit or exert their own pressure. Thus, the answer to this item should be false.