The density of copper is listed as 8.94 g/cm3. two students each make three density determi-nations of samples of the substance. student a's results are 7.3 g/ml, 9.4 g/ml, and 8.3 g/ml. student b's results are 8.4 g/cm3, 8.8 g/cm3, and 8.0 g/cm3. compare the two sets of results in terms of precision and accuracy.

Student a's results are not precise nor accurate, while Student b's results can be considered as precise but not accurate.

Explanation:

First let's start by defining the concepts of precision and accuracy.

Precision refers to how close the measurements are between them, regardless of whether they approach the actual value.

That is, if when making a measurement the result is repeated several times, it is said that the measurement is precise.

Accuracy refers to how close the measurements are to the real value.

That is, if the measurement is closer to the true value it means that it is accurate.

Now, a result can be precise but not accurate, or accurate but not precise, or both precise and accurate.

In this sense, Student a's results are not precise nor accurate, since the results are not close to the actual density of copper and are not repeated. On the other hand, Student b's results can be considered as precise but not accurate.

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l