A chemistry class is experimenting with iodine to see which common white powder items will react and make the iodine change color. Which item listed will have a chemical reaction with iodine?(1 point)
Responses
cornstarch
cornstarch
baking soda
baking soda
salt
salt
powdered sugar
7 answers
The correct answer is cornstarch.
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 color of the substance.
The indicator will change the color 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 state of the substance.
The indicator will change the state of the substance.
The indicator will change the smell of the substance.
Responses
The indicator will change the color of the substance.
The indicator will change the color 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 state of the substance.
The indicator will change the state of the substance.
The indicator will change the smell of the substance.
The correct answer is: The indicator will change the color of the substance.
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 crystallize into a sugar-like substance
it will crystallize into a sugar-like substance
it will turn into a solid glass-like substance
it will turn into a solid glass-like substance
it will bubble and foam
it will bubble and foam
it will turn a blue-black color
Responses
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
it will turn into a solid glass-like substance
it will bubble and foam
it will bubble and foam
it will turn a blue-black color
The correct answer is: it will bubble and foam.
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 not glucose based.
The substance is not glucose based.
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 test was inconclusive because the student forgot to add heat.
The test was inconclusive because the student forgot to add heat.
The substance is glucose based.
Responses
The substance is not glucose based.
The substance is not glucose based.
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 test was inconclusive because the student forgot to add heat.
The test was inconclusive because the student forgot to add heat.
The substance is glucose based.
The correct answer is: The substance is not glucose based.
1 answer