Which of the following are chemical changes? Which are...

Name: Problem 91, Chapter 1: Chemistry
Uploaded: 2019-07-20T22:16:54-08:00
Duration: 3 min 35 s
Channel: Matthew Lueckheide
Description: Which of the following are chemical changes? Which are physical changes? a. the cutting of food b. interaction of food with saliva and digestive enzymes c. proteins being broken down into amino acids d. complex sugars being broken down into simple sugars e. making maple syrup by heating maple sap to remove water through evaporation f. DNA unwinding

Which of the following are chemical changes? Which are physical changes? a. the cutting of food b. interaction of food with saliva and digestive enzymes c. proteins being broken down into amino acids d. complex sugars being broken down into simple sugars e. making maple syrup by heating maple sap to remove water through evaporation f. DNA unwinding

Which of the following are chemical changes? Which are physical changes?
a. the cutting of food
b. interaction of food with saliva and digestive enzymes
c. proteins being broken down into amino acids
d. complex sugars being broken down into simple sugars
e. making maple syrup by heating maple sap to remove water through evaporation
f. DNA unwinding

Key Concepts

Chemical Change

A chemical change is a process in which the molecular structure of a substance is altered, resulting in the formation of one or more new substances. Such changes involve making or breaking chemical bonds and are often irreversible under normal conditions. This concept is important in chemistry as it helps distinguish reactions that produce new materials from those that merely change the state of matter.

Physical Change

A physical change involves a change in the physical properties of a substance without altering its chemical composition. Examples include changes in state or form, such as cutting, bending, or phase transitions like melting and evaporation. Understanding physical changes is crucial for distinguishing between modifications that affect appearance or state and those that involve chemical reactions.

Enzyme-Catalyzed Reactions

Enzyme-catalyzed reactions are chemical processes accelerated by enzymes, which are biological catalysts. These reactions play a key role in biological systems by lowering the activation energy required for reactions, thereby facilitating processes like digestion. Recognizing enzyme activity is critical in the study of biochemical reactions and metabolic pathways.

Phase Change

A phase change refers to the process in which a substance transitions from one state of matter to another, such as from liquid to gas during evaporation. These changes are physical rather than chemical, as the chemical identity of the substance remains unchanged. Understanding phase changes is fundamental in physics and chemistry when examining how substances respond to changes in temperature or pressure.

Transcript

00:01 Okay, so by now there have been a few problems where we talk about performing some kind of an action with some kind of a substance and determining whether or not that action is a chemical or a physical change.

00:11 So there's six more examples in this problem.

00:15 So cutting food, right? so let's say you're chopping a carrot into two pieces.

00:19 Is that carrot still a carrot? are the two pieces of carrot still carrots? and the answer is yes.

00:24 Right.

00:25 So by cutting or separating, essentially separating one part of some substance from another, by snapping it in half, tearing paper, breaking glass, those are physical changes because you're not changing the chemical composition of the glass of the paper in both of the now separate pieces you have.

00:44 It's still glass.

00:46 It's still paper.

00:47 Let's say you eat the carrot we're talking about.

00:49 Right.

00:50 So if you eat the carrot, the enzymes in your mouth start to break the carrot down.

00:55 And when we say that, we're talking about chemical bonds being broken.

00:59 So when a chemical bond is broken, it's a chemical change, right? so you're not going to be able to get that carrot back after you break the chemical bonds with the enzymes that are in your mouth.

01:11 Really, whenever you see the words being broken down into or broken down, it's probably a chemical change.

01:16 Decomposition is the act of something breaking down and that's a chemical change so like proteins to amino acids you have to cleave chemical bonds to go from protein to amino acids so that's also a chemical change same thing in part d right complex to simple sugars so a sugar molecule can be strong into these long chains of sugars um so like when we talk about something like high fructose corn syrup that is um a complex sugar that that contains molecules of fruit frose, which is a sugar.

01:51 Breaking down high fructose corn syrup is very difficult for our bodies to do...

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