Astudent is given a sample of a calcium sulfate hydrate. he places the sample in a dry, covered crucible and weighs it. the total mass (crucible, cover, and hydrate) is 18.89918.899 g. the crucible and cover together had previously weighed 17.65517.655 g. he then heats the crucible to redness for 10 minutes with the cover slightly ajar. after the crucible cools, he weighs the crucible and its contents; the mass is now 18.63918.639 g, due to the loss of water of hydration. what is the mass of the original sample? mass of original sample : g what is the mass of the anhydrous (dehydrated) sample? mass of anhydrous sample : g what is the mass of the water that is driven off? mass of water driven off :

Change in speed or direction : )

What record? the question is incomplete

Use the universal gas law formula: pv = nrt now, the key word in this problem is stp, so at stp, temperature will always be 0 degrees celsius and pressure will always be 1.0 atm or 760 torr. given something is at stp, we already know the two variables pressure and temperature. the other thing we can find with the given information is moles. to find moles, just divide grams by molar mass of the element. 16.0g / 2(16.00)g/mol = 0.5 moles plug the values in to the equation pv = nrt (1.0 atm)( x ) = (0.5 )(0+273=273k) the r value is just a constant for when we use atm, liters, moles and kelvin. i'm assuming you want your answer in liters, but if you dont just move the decimal 3 to the right in your final answer. so when plugging these numbers in to your calculator and trying to find x, you get 11.20665 liters using significant figures the answer is 11.2 liters

The surface of the water droplet is held together by the attraction between molecules. in order for water to flow more easily into these small spaces, you need to decrease its surface tension. you can do this by adding soap, which is a surfactant (a material that decreases the surface tension of a liquid).