For part of our orbit the northern half of Earth is tilted toward the Sun. This is summer in the northern hemisphere; there are longer periods of daylight, the Sun is higher in the sky, and the Sun's rays strike the surface more directly, giving us warmer temperatures.
The percent yield of a chemical reaction is calculated by dividing the actual yield (determined through experimentation) by the theoretical yield (calculations). The percent yield is a great way of determining the efficiency of a reaction. For this problem, the percent yield is 83.93% as given by the solution:
% yield = (47/56)*100 = 83.93%