Evaluate the product. (7.61×10^9)(4.46×10^3)

3. Now let's suppose it's your turn to be the professor. You want to write a question for your students using theoretical data. Suppose you want their "unknown liquid" to be toluene (molar mass = 92.1 g/mol). Using the data in the table below, what should the "mass of flask + unknown condensed liquid" be so that they can correctly identify toluene as their unknown? Mass of flask: 77.485 g Mass of flask + unknown condensed liquid: ????? Temperature of water bath: 100 °C Pressure of gas in our system: 0.997 atm Volume of gas in our system: 255 mL Group of answer choices: A) 78.250 B) 0.765 C) 1.04 g D) 78.525 g

5a) A student strongly heated 3.67 g hydrated calcium chromate in a crucible. After several heatings, the mass of the anhydrous salt was 2.98 g. Based on the student's lab data, calculate the percent of water in the hydrated calcium chromate. b) Use the data given in 5a above to determine the formula of the hydrate. You need to figure out the moles of dry salt and the moles of water and compare the two. You need the specific formula of calcium chromate in order to find the number of moles. Write the formula of the hydrate including ratio to the 0.01 place. It should look like this: salt-x.xx H₂O (fill in the ratio just determined for the x's).

Caffeine (MM = 194.2 g/mol) is a small molecule that many people ingest for its stimulant effects. Elemental %3D analysis shows that this compound contains 49.5% C, 5.19% H, 28.9% N and 16.5% O by mass. (a) Determine the empirical formula of Caffeine? (b) Determine the molecular formula of Caffeine? Clearly show your work.