Carefully add HNO into the flask until the phenolphthalein begins to lose its color. Stop adding HNO3 when the color change is permanent.

A. How much (HNO3) was required to cause the indicator to change color?

B. What can you say about the pH before and after the last drop of HNO3 was added?

Asample of radium-226 will decay 1/4 of its original amount after 3200years. what is the half-life of radium-226?

Nitrogen (n), phosphorus (p), and potassium (k) are the main nutrients in plant fertilizers. according to an industry convention, the numbers on the label refer to the mass percents of n, p2o5, and k2o, in that order. calculate the n: p: k ratio of a 30: 10: 10 fertilizer in terms of moles of each element, and express it as x: y: 1.0.

Which element would mostly likely have an electron affinity measuring closest to zero