Answer
B. One element takes the place of another in a compound
Explanation
A single-replacement reaction occurs when one element is substituted for another element in a compound.The reacting materials are normally pure elements such as a metal or hydrogen gas with an aqueous compound.A new aqueous compound plus a different pure element are formed as products.
Acidic and basic are two extremes that describe chemicals, just like hot and cold are two extremes that describe temperature. Mixing acids and bases can cancel out their extreme effects, much like mixing hot and cold water can even out the water temperature. A substance that is neither acidic nor basic is neutral.
The character of acidic, basic and neutral is defined by the concentration of hydrogen ions [H+](mol/L). A solution with a concentration of hydrogen ions higher than 10-7mol/L is acidic, and a solution with a lower concentration is alkaline (another way to say basic). Using the formula, pH=-log[H+], a pH of 7 is neutral, a pH less than 7 is acidic, and a pH greater than 7 is basic. As one can see from this formula, ten times a given concentration of hydrogen ions means one unit lower in terms of pH value (higher acidity), and vice versa.
The formula for ph is given by:pH=−log10[H+]
What is the concentration of H+ ions at a pH = 8?
In calculating for the concentration of hydrogen ion, the formula is given by:[H+]=(10)^(-pH)
Solution:
[H+]=(10)^(-8)[H+]=0.00000001 mol/L
What is the concentration of OH– ions at a pH = 8?pH+pOH=148+pOH=14pOH=6
[OH-]=(10)^(-pOH)[OH-]=(10)^(-6)[OH-]=0.000001
What is the ratio of H+ ions to OH– ions at a pH = 2?The ratio is 0.00000001:0.000001 which is equal to 0.01
Answer:
A) covalent bond
Explanation:
Covalent bonding generally happens between nonmetals.
Answer:
not valid
Explanation:
Expert judgment is a useful validation method to verify the reliability of an investigation that is defined as “an informed opinion of people with experience in the subject, who are recognized by others as qualified experts in it, and who can give information, evidence, judgments and assessments ”
After submitting an instrument for comparison to the consultation and expert opinion, it must meet two quality criteria: validity and reliability. The validity of content is often established based on two situations, one that concerns the design of a test and the other, the validation of an instrument subject to translation and standardization procedures to adapt it to different cultural meanings. It is here that the task of the expert becomes a fundamental task to eliminate irrelevant aspects, incorporate those that are essential and / or modify those that require it.
