Experiment #1: Change the color with your breath! The secret to this experiment is a pH indicator called bromothymol blue. The bromothymol blue turned yellow in the presence of the vinegar, but remained blue in the presence of the baking soda.

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What color does Bromothymol blue change to?

Bromthymol blue changes color over a pH range from 6.0 (yellow) to 7.6 (blue). It is a good indicator of dissolved carbon dioxide (CO2) and other weakly acidic solutions.

What happens when you mix calcium chloride and Bromothymol blue?

Bromothymol blue is an acid–base indicator that changes color in the presence of acids and bases. As sodium bicarbonate reacts with calcium chloride in water, acidic substances are produced and the color of the Bromothymol blue indicator changes from the basic form to its yellow, acidic form.

What does Bromothymol blue indicator indicate?

Bromothymol blue (also known as bromothymol sulfone phthalein and BTB) is a pH indicator. It is mostly used in applications that require measuring substances that would have a relatively neutral pH (near 7). A common use is for measuring the presence of carbonic acid in a liquid.

Why is bromophenol blue a good indicator?

As an acid–base indicator, its useful range lies between pH 3.0 and 4.6. It changes from yellow at pH 3.0 to blue at pH 4.6; this reaction is reversible. Bromophenol blue is structurally related to phenolphthalein (a popular indicator).

Is Bromothymol Blue a universal indicator?

A universal indicator is a pH indicator made of a solution of several compounds that exhibits several smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions….Universal indicator.

IndicatorLow pH colourTransition pH rangeHigh pH colour
Bromothymol blue
6.0 – 7.6

What Colour does Bromothymol blue turn in acid?


What Colour is the universal indicator?

The Universal Indicator Color Guide shows that Universal Indicator turns red when it is added to a strong acid, it turns purple when it is added to a strong base, and it turns a yellowish-green when it is added to a neutral solution. All acids in the range of 1 to 4 turn the indicator red.

What causes the color of Bromothymol Blue to change after blowing bubbles into it?

why did you blow bubbles into the tube? a slight increase of the bromothymol blue solution, as when carbon dioxide is added, will make the solution acidic and the color will change from blue to green.

When someone breathes into Bromothymol blue and it turns green or yellow Why does it do that?

Breathing rate increases with in increase of physical activity. Bromothymol blue is in indicator for carbon dioxide which means that it will change color if carbon dioxide is present. Bromothymol blue solution changes color from blue to green or from blue to yellow when carbon dioxide if bubbled into it.

What color is Bromothymol blue in neutral solutions?


What is BTB changing color evidence for and why?

Bromothymol blue solution, BTB, can indicate the presence of carbon dioxide in the water. When little or no carbon dioxide is present, BTB will show a blue color. Depending upon the amount of carbon dioxide, BTB will change to green or yellow. Yellow indicates more carbon dioxide.

Is BTB toxic?

Ingestion: May cause gastrointestinal irritation with nausea, vomiting and diarrhea. May be harmful if swallowed. Inhalation: May cause respiratory tract irritation. May be harmful if inhaled.

Does your body breathe out CO2?

When we take a breath, we pull air into our lungs that contains mostly nitrogen and oxygen. When we exhale, we breathe out mostly carbon dioxide.

How can BTB be used to show that something is living?

BTB, can indicate the presence of carbon dioxide in water. When little or no carbon dioxide, BTB will show a blue color. Green plants use energy from light to combine carbon dioxide and water to make food ( glucose) . They release oxygen (O2) as a waste product.

Can BTB go back blue?

15. BTB (Bromothymol Blue) is a blue solution. It turns yellow in the presence of carbon dioxide. The BTB would turn Blue.

What will happen if the elodea plant is left in the dark?

Elodea needs the requirements to carry out photosynthesis, but being placed in the dark it can not do so. However it continues to carry out cellular respiration which results in the increase of carbon dioxide level in the water.

What happens to BTB in the dark?

The BTB turned yellow because of the carbon dioxide. Both plants are doing cellular respiration, and by doing that they are producing carbon dioxide. The plant in light is using the CO2 to do photosynthesis, but the plant in dark isn’t doing photosynthesis and storing up CO2 which turns the BTB yellow.

What do the colors of BTB indicate?

BTB is an acid indicator; when it reacts with acid it turns from blue to yellow. When carbon dioxide reacts with water, a weak acid (carbonic acid) is formed (see chemical reaction below). The more carbon dioxide you breathe into the BTB solution, the faster it will change color to yellow.

Is there carbon dioxide in the air we breathe in?

The air we breathe contains vital respiratory gases and a lot more besides. The main components are nitrogen, oxygen, argon and carbon dioxide. But it also contains particulate matter that can harm us.

How do you make Bromothymol blue?

Combine 20 mL of alcohol to the sodium hydroxide/bromothymol blue solution. Dilute the mixture with 1 L of distilled water in a large container. The solution should be dark blue in color. If the solution appears green, use a pipette to slowly add sodium hydroxide drop by drop to the solution until it changes to blue.

What can I use instead of Bromothymol blue?

If you are just looking for bubbles baking soda would work.

Is Bromothymol blue edible?

The bromothymol blue powder can cause skin and eye irritation, as well as acute toxicity if swallowed. Small unintentional digestion has seen no issues, but high levels can cause nausea and vomiting, even death. Incidental swallowing can be treated by drinking water.

Where can I get Bromothymol blue?


How does bromophenol blue work?

General description. Bromophenol Blue is a pH indicator, and a dye appearing as a strong blue color. Bromophenol blue has a slight negative charge and will migrate the same direction as DNA, allowing the user to monitor the progress of molecules moving through the gel. The rate of migration varies with gel composition.

Does Bromothymol blue expire?

Theoretically under the right conditions, you could use the chemicals 20 years from now.

Does Bromothymol blue change pH?

Bromothymol blue is a chemical indicator that turns blue at a pH value greater than 7. Bromthymol blue changes color over a pH range from 6.0 (yellow) to 7.6 (blue). It is a good indicator of dissolved carbon dioxide (CO2) and other weakly acidic solutions.

What does it mean when Bromothymol blue turns green?

Bromothymol blue (BMB) is an indicator dye that turns yellow in the presence of acid. When carbon dioxide is added to the solution, it creates carbonic acid, lowering the pH of the solution. BMB is blue when the pH is greater than 7.6, green when the pH is between 6-7.6, and yellow when the pH is less than 6.

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What would happen if Bromothymol Blue was put in an acid solution?

When you add acid, bromothymol blue turns yellow; when you add a base (like sodium sulfite), it turns blue. Green means neutral (like water).