For a chemistry class, a student's grades are weighted as follows: quizzes are 30%, exams are 40%, and the final exam is 30%.   If a student scored 90, 75, and 80 on the quizzes, exams, and final respectively, calculate the student's final grade. Express your answer to three significant figures

Suppose you are trying to find the volume of a box based on the given measurements for the length, width, and height of the box, where the height was measured in two parts.      length, l = 2.20 in      width, w = 3.71 in      height, h = 10.4 in + 1 in Calculate the height, ℎ, of the box, first keeping all digits, then rounding to the proper number of significant figures. unrounded h = ____in rounded h =____  in  Calculate the volume (V) of the box using V =l x w x h. Round to the proper number of significant figures.  v=_____in3

A chemistry student weighs out 0.0176 g of formic acid (HCHO2)into a 250. mL volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with 0.1300 M(molarity) NaOH solution. Calculate the volume of NaOH solution the student will need to add to reach the equivalence point. Round your answer to 3 significant digits.

If a sample of gold alloy has a mass of 87.7 g and is 78.3% gold by mass, what percentage of the alloy is made up of other metals? Write your answer to the nearest tenth of a percent. (I had to alter the wording of this question since it wasn't calculating significant figures properly, so if you got it wrong because of significant figures you can assume you probably actually got it correct.)

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What do the abbreviations in the equations below mean?  (write next to the equations)   C  +  MU  =  R   C%  +  MU%  =  100%   MU%  =    MU   × 100%                      R     C%  =   C   × 100%    R

A chemistry student weighs out 0.0960 g of phosphoric acid (H,PO4), a triprotic acid, into a 250. mL volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with 0.1100 M NaOH solution. Calculate the volume of NaOH solution the student will need to add to reach the final equivalence point. Round your answer to 3 significant digits. |mL ola х10 Ar

How many molecules are contained in 5.00 microliters of methanol (CH4O)? The density of methanol is 0.792 g/mL. Use these atomic masses: C = 12.011 amu; H = 1.008 amu; O = 15.999 amu. Input your result in scientific notation using the format with the lower case e representing the x10. For example, in this format the number 1.234x109 would be expressed as 1.234e9. The number 1.234x10-9 would be expressed as 1.234e-9  Not these answers  0.1569 1.23 0.1569 0.0001

I don't understand the wording. The least significant digit means the last digit?  7.700 X 2.1 = 16.17     would the uncertainty be  0.01 ? 2.132 + 17 + 4.04 = 23.172   would the uncertainty be 0.001 ?

The world population is estimated to be 7.4 x 109. Nauru is the smallest island nation and comprises 1.5 x 10-4% of the world population. If the percentage of left-handed people is approximately 12%, estimate the number of left-handers on the island of Nauru.