(Q).
Q: How does litmus paper indicate the ph value of a solution? Read this paragraph and choose the correct option from the provided answers: There are two common ways to measure pH. When only an approximate pH value is needed, an inexpensive test involves the use of acid-base indicators , which change color based on the relative acidity of the solution. One type of common indicator is litmus paper. For example, if a piece of litmus paper is dipped into an acidic solution (pH below ~4.5), it will turn red, and dipping it into a basic solution (pH above ~8.5) will turn it blue. Solutions of intermediate pH will result in various shades of purple. Because different indicators change color at different pH values, the use of multiple indicators can generally narrow down the possible pH of a solution to a range of about 0.5-1 pH units. Figure below shows the colors exhibited by various indicators at different pH values. Choices: - by texture - by shape - by smell - by color A:
(A).
by color

(Q).
Q: What element is a biochemical compound based on? Read this paragraph and choose the correct option from the provided answers: Besides water, most of the compounds in living things are biochemical compounds. A biochemical compound is a carbon-based compound that is found in living organisms. Carbon is an element that has a tremendous ability to form large compounds. Each atom of carbon can form four chemical bonds with other atoms. A chemical bond is the sharing of electrons between atoms. Bonds hold the atoms together in chemical compounds. A carbon atom can form bonds with other carbon atoms or with atoms of other elements. Choices: - hydrogen - nitrogen - oxygen - carbon A:
(A).
carbon

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Q: Felsic, intermediate, mafic, and ultramafic are types of composition of what rock group? Read this paragraph and choose the correct option from the provided answers: Igneous rocks are classified by composition and texture. The composition can be felsic, intermediate, mafic, or ultramafic. The composition depends on the minerals the rock includes. A felsic rock will contain felsic minerals. Choices: - Sedimentary - asteroids - metamorphic - igneous A:
(A).
igneous