40g of impure calcium carbonate reacts with 200cm^3 of a dillute sulphuric the calcium carbonate sulphric acid react completely leaving the impurities unreacted at the competition of the reaction. Calculate the percentage purity​

An insurance company wants to know if the average speed at which men drive cars is higher than that of women drivers. the company took a random sample of 27 cars driven by men on a highway and found the mean speed to be 72 miles per hour with a standard deviation of 2.2 miles per hour. another sample of 18 cars driven by women on the same highway gave a mean speed of 68 miles per hour with a standard deviation of 2.5 miles per hour. assume that the speeds at which all men and all women drive cars on this highway are both approximately normally distributed with unknown and unequal population standard deviations.

Select the correct answer from each drop-down menu. compared to its surroundings, the concentration of solutes is low inside a cell. so, the cell is with respect to its surroundings. a particular solute in this cell uses energy for its transport from the cell to its surroundings. this type of transport is called

Unpolarized light of intensity so passes through two sheets of polarizing material whose transmission axes make an angle of 60∘ with each other as shown in the figure. what is the intensity of the transmitted beam, st?