Iknow this isn't a math question, but i have received no answers in the chemistry section of this site. can anyone in here with this question? i cannot find the answer to this anywhere in my chem book: what is the major difference between the two-dimensional and three- dimensional models of ethane and methane? when might you choose to use a two-dimensional model rather than a three-dimensional model when representing one of the molecules?

Acylinder has volume 45π and radius 3. what is it’s height?

Ineed the answers for this one as well!

Anull hypothesis states that the difference between 8 hours of sleep and 3 hours of sleep has no effect on the number of pictures a student will remember during a picture memory interface test (pmit). examining the mit database, an extremely small t-value of 0.1611 is found. this t-value is much smaller than the smallest t-value on the chart for p-value reference. from this information we can: select one: a. accept the null hypothesis because the p-value obtained shows that the difference between the two groups being tested is not statistically significant b. accept the null hypothesis because the p-value obtained was statistically significant c. reject the null hypothesis because of the p-value obtained d. reject the null hypothesis because the data obtained is statistically significant