The correct response is:
The indicator will change the color of the substance.
In the case of starch, a common indicator is iodine, which changes color to blue-black when it comes into contact with starch.
When performing a scientific investigation on an unknown substance, how can an indicator help you determine if the substance is a starch?(1 point)
Responses
The indicator will change the state of the substance.
The indicator will change the state of the substance.
The indicator will change the taste of the substance.
The indicator will change the taste of the substance.
The indicator will change the smell of the substance.
The indicator will change the smell of the substance.
The indicator will change the color of the substance.
11 answers
A student has an unknown powder and wants to determine what it is. Based on appearance, the student believes it is baking soda. When performing the vinegar test, what can the student expect to happen if it is baking soda?(1 point)
Responses
it will bubble and foam
it will bubble and foam
it will turn a blue-black color
it will turn a blue-black color
it will crystallize into a sugar-like substance
it will crystallize into a sugar-like substance
it will turn into a solid glass-like substance
Responses
it will bubble and foam
it will bubble and foam
it will turn a blue-black color
it will turn a blue-black color
it will crystallize into a sugar-like substance
it will crystallize into a sugar-like substance
it will turn into a solid glass-like substance
The correct response is:
it will bubble and foam.
When baking soda (sodium bicarbonate) is mixed with vinegar (which contains acetic acid), a chemical reaction occurs that produces carbon dioxide gas, resulting in bubbling and foaming.
A student is performing a Benedict’s test on an unknown substance. The student adds the reagent (the chemical required to make a color change), and nothing happens. Which conclusion can the student make?(1 point)
Responses
The substance is glucose based.
The substance is glucose based.
The test was inconclusive because the student forgot to add heat.
The test was inconclusive because the student forgot to add heat.
The test was inconclusive because the student needed to also test with iodine or vinegar.
The test was inconclusive because the student needed to also test with iodine or vinegar.
The substance is not glucose based.
Responses
The substance is glucose based.
The substance is glucose based.
The test was inconclusive because the student forgot to add heat.
The test was inconclusive because the student forgot to add heat.
The test was inconclusive because the student needed to also test with iodine or vinegar.
The test was inconclusive because the student needed to also test with iodine or vinegar.
The substance is not glucose based.
The correct response is:
The substance is not glucose based.
Benedict's test is specifically used to detect reducing sugars, including glucose. If the reagent is added and no color change occurs, it indicates that the unknown substance is likely not glucose or another reducing sugar. However, it's important to note that while this suggests the absence of glucose, there may be other reasons for a lack of reaction, such as incorrect procedure, but based on the provided options, this is the most direct conclusion.
How did the last ice age affect human migration?
(1 point)
Responses
It created land bridges where ocean had once been.
It created land bridges where ocean had once been.
It required people to create new shelters.
It required people to create new shelters.
It required people to form larger communities.
It required people to form larger communities.
It required people to live closer together.
It required people to live closer together.
(1 point)
Responses
It created land bridges where ocean had once been.
It created land bridges where ocean had once been.
It required people to create new shelters.
It required people to create new shelters.
It required people to form larger communities.
It required people to form larger communities.
It required people to live closer together.
It required people to live closer together.
The correct response is:
It created land bridges where ocean had once been.
During the last ice age, lower sea levels due to the accumulation of ice sheets exposed land bridges, such as the Bering Land Bridge between Asia and North America, facilitating human migration to new regions.
Use the drop-down menus to complete the sentence.
(1 point)
In the struggle to survive,
Choose
gave
Choose
a great advantage because they could then organize a hunt and pass knowledge on to their young.
(1 point)
In the struggle to survive,
Choose
gave
Choose
a great advantage because they could then organize a hunt and pass knowledge on to their young.
In the struggle to survive, social structures gave early humans a great advantage because they could then organize a hunt and pass knowledge on to their young.
the options are 1; Fire, Hunting animals, complex language, making tools. and 2; Homo sapiens, Neanderthals, homo habilis, Gilgamesh
Based on the options provided, the completed sentence would be:
In the struggle to survive, complex language gave Homo sapiens a great advantage because they could then organize a hunt and pass knowledge on to their young.
1 answer