ACT Science 2

A researcher is conducting an experiment in a solution that becomes basic upon completion. According to Figure 1, the reaction is complete when:

• the addition of bromocresol green results in a blue color.

• any indicator turns violet.

• any indicator turns blue.

• the addition of bromothymol blue results in a blue color.

   

Tags

NGSS.MS-PS1-2

Suppose that a researcher has two test tubes of an identical solution. When bromocresol green is added to one test tube, it turns blue, and when phenolphthalein is added to the other test tube, it is colorless. According to Figure 1, which of the following could be the pH of the solution?

 

• 6

• 7

• 7.5

• 8.5

Tags

NGSS.MS-PS1-2

Which of the following indicators undergo a color change between pH 7 and pH 10?

 

• Bromocresol green and bromothymol blue

•   Phenolphthalein and thymol blue

• Alizarin and sodium indigo sulfonate

• Phenolphthalein and bromothymol blue

Tags

NGSS.MS-PS1-2

Which of the following hypotheses is consistent with the information in Figure 1?

• Color changes for all acid-base indicators occur in solutions with a pH less than 7.

•   Color changes for all acid-base indicators occur in solutions with a pH greater than 7.

• Color changes for acid-base indicators can always be used to determine if a solution is either acidic or basic.

• Color changes for acid-base indicators vary within the pH range.

Tags

NGSS.MS-PS1-2

Compared to bromothymol blue, phenolphthalein undergoes a color change at:

• a higher pH level because it reacts in more basic solutions.

• a  lower pH level because it reacts in more basic solutions.

• a higher pH level because it reacts in more acidic solutions.

• a lower pH level because it reacts in more acidic solutions.

Tags

NGSS.MS-PS1-2

Black coffee has a pH of approximately 5. A researcher wants to determine whether adding milk causes coffee to change pH; if the coffee could be diluted so that it does not interfere with the color displayed by an indicator, which of the following indicators would be the most useful?

• Methyl orange

• Bromothymol blue

• Bromocresol green

• Alizarin

Tags

NGSS.MS-PS1-2

In a binary star system, the orbital period for a star is the time it takes that start to complete one full prbit around the other star. The orbital period for Star 2 is about:

• 4 days

• 10 days

• 12 days

• 20 days

Tags

NGSS.HS-ESS1-4

The point in Figure 1 labeled c corresponds to which position for Star 2 in Diagram 1?

• 1

• 2

• 3

• 4

The eclipsing binary stars in System Q alternately eclipse each other for periods of approximately:

• 2 days and 4 days

• 3 days and 4 days

• 3 days and 8 days

• 5 days and 8 days

Tags

NGSS.HS-ESS1-4

Which of the following hypotheses would best explain why System Z has a deeper primary minimum than System X?

• There is a more extreme difference between the magnitudes of the two stars in System X than between the magnitudes of the two stars in System Z.

• There is a more extreme difference between the magnitudes of the two stars in System Z than between the magnitudes of the two stars in System X.

• The orbital period of System X is longer than the orbital period of System Z.

• The orbital period of System Z is longer than the orbital period of System X.

Tags

NGSS.MS-PS2-4

NGSS.MS-PS3-1