Answer:
Mass of chemical = 1.5 mg
Explanation:
Step 1: First calculate the concentration of the stock solution required to make the final solution.
Using C1V1 = C2V2
C1 = concentration of the stock solution; V1 = volume of stock solution; C2 = concentration of final solution; V2 = volume of final solution
C1 = C2V2/V1
C1 = (6 * 25)/ 0.1
C1 = 1500 ng/μL = 1.5 μg/μL
Step 2: Mass of chemical added:
Mass of sample = concentration * volume
Concentration of stock = 1.5 μg/μL; volume of stock = 10 mL = 10^6 μL
Mass of stock = 1.5 μg/μL * 10^6 μL = 1.5 * 10^6 μg = 1.5 mg
Therefore, mass of sample = 1.5 mg
The correct answer is A. A test tube of zinc oxide. Zinc oxide is a compound which is a pure substance composed of two or more elements. They can only be separated or broken down into its individual elements or smaller compounds by chemical means. Therefore, the answer is a test tube of zinc oxide.
B. Molecules in both the metal and the surrounding air will start moving at higher speeds.
The most basic level of organization that is involved in converting fuel or food into forms of energy, are found and compose living things. These are called cells.
