The mass of a sample of sodium bicarbonate is 2.1 kilograms (kg). there are 1,000 grams (g) in 1 kg, and 1 mc020-1.jpg 109 nanograms (ng) in 1 g. what is the mass of this sample in ng? 2.1 mc020-2.jpg 103 ng 2.1 mc020-3.jpg 106 ng 2.1 mc020-4.jpg 109 ng 2.1 mc020-5.jpg 1012 ng

Well you can immediately rule out a and d because if a metal were to lose or gain protons, then it would become a different element all together. the answer here is b because the positive symbol with a number refers to how many electrons the metal can give away to become stable.

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