Question 11 (3 points) The table below shows the initial masses of four stars.
Name of Star
Star Star Star Star
1 2 3 4
Initial mass of star
(in Solar mass)
9
0.9
5
0.3
Which of these stars will stay on the main sequence for the shortest time?
Star 1
Star 4
Star 3
Star 2

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

Is 9 correct? and can someone me with 10? it’s due tomorrow, you