The answer to #11 and why that's the correct answer
1 answer:
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Answer: B. warming ice to produce water
Explanation:
A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions. Example: Melting of ice
A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions. Example: Corrosion of iron called as rusting.
Endothermic reactions are those in which heat is absorbed by the system and exothermic reactions are those in which heat is released by the system.
A. heating a rock to make it hot : It requires addition of energy and does not involve any change.
B. warming ice to produce water : It requires addition of energy and is a physical change
C. igniting a hydrogen-filled balloon: It needs energy and is a chemical change
D. burning paper to produce and carbon : It releases energy and is a chemical change
Answer:
A central C is double bonded to an O, and single bonded to 2 H
Explanation:
Methanal, also known as formaldehyde, is a chemical compound used to preserve dead biological specimens for further study. It is called formalin when in a solution and it helps keep specimens in a fresh state by hardening the tissues of the specimen involved.
Formaldehyde is a gaseous compound that has an aldehyde functional group i.e. -CHO and has a chemical formula, H-CHO or CH2O as described in the question that a central C is double bonded to an O, and single bonded to 2 H (see attached image for structural formula).
