400 mL of a mixture of hydrogen and oxygen in the proportion of 3 volumes to 1 volume respectively is measured
338330
The answer to this is made tougher by the fact that the water will be freezing.  I mean how can you answer a question where the water is ice cold and use the data provided at STP?  Think you need to either re-read your question or provide a little more info.
212429
dots..\nits jux 2 hydrogen and 1 oxygen for every mole of h2o
354284
The volumne of a gas increases to fill its container and both H and O are gases at room temperature.  Is volume really what you want to know?
704981
V = LWH\nV = (200cm)(200cm)(1cm)\nV = 40000 ml\nV = 40 Liters
319335
It's liquid hydrogen and oxygen.  I imagine they just make it in a factory by cooling down those gases to very low temperatures.
754271
2H2 + O2 --> 2H2O\nPV = nRT\nP = 2 + 3 = 5\nT = 25 + 273 = 298\n5.00 atm x 55.0 L = n x .08206 x 298\nn = 11.25 mol H2 and O2 mixture\n11.25 mol x (2 mol H2O / 3 mol) = 7.50 mol H2O\n\nP x 55.0 = 7.50 x .08206 x 298\nP = 3.33 atm
953114
Solid,liquid and gas.
146549
its not volts its volume. 1o volume is equal to 3% hydrogen peroxide.
724819
To determine the concentration of a reagent.
4678
to find this answer....assuming ideal mixtures and complete disassociation.  \n\nM1V1=M2V2\n\nso take .450*300/4 = 33.75
144551
since the density is 1 it doesn't matter how the % was calculated. usually you need to be specific.\n3% is 3mls peroxide/100 mls or 30 mls(30gms)/1 L\n30/molar mass = 0.88M for concentration.
823430
the buoyancy of the object and its volume.
860910
Pour the liquid in the graduated cylinder and there will usually be mL markings along the side.  This measurement is volume
139469
16.45 mL HNO3 solution * [1 liter/1000 mL] * [0.302 moles HNO3/1 liter HNO3 solution] * [1 mol NaOH/1 mol HNO3] * [1 liter NaOH solution/0.250 mol NaOH] * [1000 mL/1 liter]\n\n=67.0 mL NaOH solution\n\nEDIT: [Sorry, the answer above was wrong; I don't know how I got that. The answer is 19.87 mL]\nEND EDIT\n\nBasically, you just use a whole bunch of ratios relating all the units and measurements together.\nIf you write all that out, all the units should cancel except the "mL NaOH solution"\nMight want to check my answer though...\n\n\nNext question:\n[16.45 ml HNO3 solution] * [1 liter/1000 ml] * [0.302 mol HNO3/1 liter HNO3 solution] * [1000 millimoles solution/1 mol solution]\n\n=4.97 millimoles HNO3 solution
259405
Total volume =( 1 + 2 ) dm3 = 3 dm3.\nUse Boyles  pV = constant on both gasses.\nThe partial pressure of helium is 2/3 kPa.\nThe partial pressure of neon is also 2/3 kPa.\nDalton's law:\nthe pressure of the mix is 2/3 kPa + 2/3 kPa = 1.3 kPa.
16164
The instruction is not correct because the total volume yielded when you mix 100ml of concentrated solution and 900ml water will be somewhat less than 1000ml. The concentration will be slightly higher than 1.0M\n\nThe correct procedure is to take a 1l volumetric flask  and add the concentrated solution to about 800ml water, then fill up to the mark.
807508
Most of the info provided is superfluous.\nSimply put, you burned something and got 4.161g H2O (MW=18.016), all H coming from the sample.\nSo you formed 4.161/18.016 = 0.23096 mols H2O, and since each mol H2O contains 2 mols H, your sample contained 0.4619 mols of H.\n\nBTW, it is easy to deduce the empirical formula of the compound:\nNo hydrocarbon can have a MW of 60.095, and since only CO2 and H2O were formed, the compound  must contain O...this works out to be C3H8O, which means it is probably propanol (n or iso) or methyl ethyl ether.