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3 years ago

When does phenolphthalein turn pink?

2 answers:

5 0

A.) Phenolphthalein is colorless in an acid, but it turns bright pink in the presence of a base.

Hope I helped you!!

Svetach [21]3 years ago

3 0

Answer is: a) in the presence of a base.

Phenolphthalein is colorless in acidic solutions and pink in basic solutions.

Acid-base indicators are usually weak acids or bases and they are chemical detectors for hydrogen or hydronium cations.

Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄).

When solution turns phenolphthalein pink, it means it is basic (pH>7).

You might be interested in

Use dimensional analysis to convert 14.5mi/hr to km/s

Liula [17]

Answer:

0.006 48 km/s

Explanation:

1. Convert miles to kilometres

14.5 mi × (1.609 km/1 mi) = 23.33 km

2. Convert hours to seconds

1 h × (60 min/1h) × (60 s/1 min) = 3600 s

3. Divide the distance by the time

14.5 mi/1 h = 23.3 km/3600 s = 0.006 48 km/s

5 0

3 years ago

Natural gas is almost entirely methane. A container with a volume of 2.65L holds 0.120mol of methane. What will the volume be if

mrs_skeptik [129]

The final volume of the methane gas in the container is 6.67 L.

The given parameters;

initial volume of gas in the container, V₁ = 2.65 L
initial number of moles of gas, n₁ = 0.12 mol
additional concentration, n = 0.182 mol

The total number of moles of gas in the container is calculated as follows;

$n_t = 0.12 + 0.182 = 0.302 \ mol$

The final volume of gas in the container is calculated as follows;

$PV = nRT\\\\\frac{V}{n} = \frac{RT}{P} \\\\\frac{V_1}{n_1} = \frac{V_2}{n_2} \\\\V_2 = \frac{V_1 n_2}{n_1} \\\\V_2 = \frac{2.65 \times 0.302}{0.12} \\\\V_2 = 6.67 \ L$

Thus, the final volume of the methane gas in the container is 6.67 L.

Learn more here:brainly.com/question/21912477

5 0

3 years ago

Determine the electron geometry (eg), molecular geometry (mg), and polarity of SO2. Determine the electron geometry (eg), molecu

Temka [501]

Answer:

See explaination

Explanation:

The electrons geometry shows the special distribution of the electrons around of the central atom of the molecule.

The molecular geometry shows the special distribution of the atoms that form the molecule.

Please kindly check attachment for further solution.

6 0

3 years ago

How many grams of nitric acid will react completely with a block of iron metal that is 4.5 cm by 3.0 cm by 3.5 cm, if the densit

denpristay [2]

Balance the equation first:

2 Fe+6 HNO3→2 Fe(NO3)3+3H2

Then calculate mass of Iron :

4.5×3.0×3.5 cm3(1 mL1 cm3)(7.87 g Fe1 ml)=371.86 g Fe

Now use Stoichiometry:

371.86 g Fe×(1 mol Fe55.85 g Fe)×(6 mol HNO32 mol Fe)=19.97 mol HNO3

Convert moles of nitric acid to grams

19.97 mol HNO3×(63.01 g HNO31 mol HNO3)=1258.3 g HNO3

7 0

3 years ago

Read 2 more answers

How are the following aspects of a reaction affected by the addition of a catalyst? 1) activation energy of the reverse reaction

snow_tiger [21]

These are four questions and four answers.

Answers:

1) activation energy of the reverse reaction

b. Decreased

2) Rate of the forward reaction

a. Increased

3) Rate of the reverse reaction

a. Increased

4) Activation energy of the forward reaction

b. decreased

Explanation:

Activarion energy is the energy required by the reactants to form the intermediate transition state and become products.

Catalysts are substances that change the path of the chemical reactions, lowering the activation energy, and thus speeding up the rate of the reactions, since the products can reach the new lower activation energy faster.

The equilibrium reactions are the chemical process in which two reactions, the forward and the reverese reactions, occur simultaneously and at the same rate. The equlibrium reactions may be represented by:

A ⇄ B

Where A → B is the direct or forward reaction, and A ← B is the reverse reaction (note the inversed arrow, from right to left).

For the direct reaction A represents the reactants and B represents the products. On the other hand, B represents the reactants and A represents the reactants of the reverse reaction and A. This, is A is the reactant of the forward reaction and the product of the reverse reaction, while B is the reactant of the reverse reaction and the product of the forward reaction.

Since, the addition of a catalyst lowers the activation energy of the process, the new activation energy is lower for both the forward and the reverse reaction, meaning that:

1. The activation energy of the reverse reaction is decreased (option b. of the first question)

2. The rate of the forward reaction is increased (option a. of the second question)

3. The rate of the reverse reaction is increased (option a. of the third question).

4. Activation energy of the forward reaction is decreased (option b. of the fourth question).

In summary, the addition of a catalyst decreases the activation energy for both forward and reverse reactions, and increases the rate of both forward and reverse reactions.

3 0

3 years ago

Read 2 more answers