Answer is: A. test and determine the pH values of unknown solutions.
Acid-base indicators are usually weak acids or bases and they are chemical detectors for hydrogen or hydronium cations (pH or pOH values).
Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄). Phenolphthalein is colorless in acidic solutions and pink in basic solutions.
Another example is methyl orange. It is red colour in acidic solutions and yellow colour in basic solutions.
Answer: The correct answer is option A.
Explanation:
An indicator is a substance which changes color to show any chemical change happening in the reaction. It gives the visible sign of any change.
Hence, main role of indicators from the given options is to determine the pH values of unknown solutions.
pH is the scale which shows the acidity and basicity of the solutions. It is the negative logarithmic value of hydrogen ion concentration of the solution. More the hydrogen ion concentration, less will be the pH and more acidic will be the solution.
The scale ranges from 0 to 14.
The value ranging from 0 to 6.9 are acidic solutions.
The value ranging from 7.1 to 14 are basic solutions.
The value having pH = 7 is neutral solution.
Indicator used to determine the pH of the solution is pH-paper which is shown in the image.
The volume measurement 0.100 L consists of 3 significant digits, counting the non-zero digit and the zero after the decimal point.
In the volume measurement 0.100 L, there are 3 significant figures. Significant figures represent the precision of a measured value. In this case, the zeroes after the decimal point are 'leading zeroes' which are not counted as significant. The '1' is a non-zero digit, which is always significant. And the zero after '1' is a 'trailing zero' that comes after a decimal point, so it is also counted as significant. Therefore, the number of significant figures in 0.100 L is 3.
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Answer;
Considering the attached image;
The correct answer is D.
Explanation;
-An element is a substance that can not be broken down into simpler substances by ordinary chemical means. Example, iron, gold, hydrogen , carbon, oxygen , etc.
-Elements are made of atoms. An atom is the smallest particle of an element that can take part in a chemical reaction. Atoms of different elements are different. Atoms of one element are basically alike.
B. energy level of outer electrons
C. nuclear charge
D. number of valence electrons
Answer:
355 ml
Explanation:
because a can of soda could't hold more than that measure.
lease company
b. At the end of a loan, the car still belongs to the lease company, but at the end of a lease the car
belongs to you.
c. A loan requires a large down payment at the beginning while a lease does not.
d. A lease requires a large down payment at the beginning while a loan does not.
Please select the best answer from the choices provided
Answer:
letter A is the answer
Explanation:
At the end of a loan the car belongs to you, but at the end of a lease, the car still belongs to the lease company.