Why is it important to rinse the buret with the chemical before starting a titration?

What is the percentage by mass of silicon (si) in iron aluminum silicate (fe3al2(sio4)3)?

Consider the following reaction at equilibrium. 2co2 (g) 2co (g) + o2 (g) h° = -514 kj le châtelier's principle predicts that the equilibrium partial pressure of co (g) can be maximized by carrying out the reaction a. at high temperature and high pressure b. at high temperature and low pressure c. at low temperature and low pressure d. at low temperature and high pressure e. in the presence of solid carbon

Which of the following describes a situation where competition between producers exists