A sample of hydrogen gas has a volume of 8.56 Lat a temperature of -10.0°C and a pressure of 153 kPa. Calculate the number of moles of hydrogen present in this gas sample

Remember to use the proper number of significant figures and leading zeros in all calculations. gelatin has a density of 1.27 g/cm³. if you have a blob of gelatin dessert that fills a 2.0 liter bottle, what is its mass? 2540 g2500 g3.9 x 10-43.937x 10-4

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.)

Ineed this awnser fast select the correct answer. this chemical equation represents the burning of methane, but the equation is incomplete. what is the missing coefficient in both the reactants and the products? ch4 + → co2 + a. 0 b. 1c. 2d. 3 e. 4