Calculate the number of hydrogen atoms in 0.25 moles of caffeine, C_8H_10N_4O_2.

Question

Calculate the number of hydrogen atoms in 0.25 moles of caffeine, C_8H_10N_4O_2. 6.02 times 10^23 .01 times 10^24 1.51 times 10624 6.02 times 10^24 1.20 times 10^24 Iron fillings in water can be separated by: crystallization acidification sublimation deposition filtration Which of the following is a heterogeneous mixture? sugar in water NaCl in water sand in water bronze vinegar Which of the following is an element? Cr NO CO_2 NH_3 SO_3 How thick is a piece of gold foil that measures 5cm on each side and has a mass of 3.87 g? The density of gold is 19.32 g/cm^3 0.16 mm 0.08 mm 0.04 mm 0.02 mm 0.01 mm The peak mount Hunter in Alaska State has an elevation of 4.442 Km. =what is this altitude in feet? (1 mi = 5280 ft = 1.609 km) 18, 345 ft 16, 158 ft 14, 577 ft 12, 615 ft 10, 960 ft Which of the following is a high-energy particle with a positive charge? gamma beta neutron proton neutrino Arsenic is best described as a Metal nonmetal metalloid novel gas Transition metal Which of the following would correctly complete this fusion reaction? How many unpaired electrons are in 0 1 2 3 4 Give the correct name for Cr_2S_3 Chromium(lll) sulfide Chromium(ll) sulfide Chromiut Chromium(lll) sulfite Chromium(ll) sulfate

Explanation / Answer

16) the hydrogen atoms in one mole of caffein = 10 X Na

Na = 6.023 X 10^23

As each molecule of Caffein consist of 10 atoms of hydrogen

So hydrogen atoms in 0.25 moles = 0.25 X 10 X 6.023 x 10^23 = 15.05 X 10^23 atoms = 1.51 X 10^24 atoms

17) Iron is insoluble in water so can be separated by filteration easily

18) Heterogeneous mixture is formed from substances which are physically distinct.

Sand in water are two substance which are physically separate from each other

19) Element: It is a chemical substance which consist of single kine of atom

So here only Chromium is element other are compounds

20) we know that density = Mass / Volume

so volume = MAss / Density = 3.87 / 19.32 = 0.200 cm^3

Volume = Length X breadth X thickness

Thickness = Volume / Length X breadth = 0.2 / 5X 5 = 0.008 cm = 0.08 mm

22) proton is positive but not high energy

Alpha is positive and high energy particle

23) arsenic is a metalloid

24) The complete equaiton will be

[two protons on reatant side, so must have to protons on product side]

There is only one proton on product side e

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