Sodium hydride reacts with excess water to produce aqueous s…

Sodium hydride reacts with excess water to produce aqueous sodium hydroxide and hydrogen gas. How many grams of NaH will produce 0.746 L of gas at 25.1oC and a barometric pressure of 765 torr, when the hydrogen is collected over water. The vapor pressure of water at this temperature is 23.9 torr.  NaH (s) + H2O (l) →  H2 (g) + NaOH (aq)

In an experiment, a student placed a beaker on a balance and…

In an experiment, a student placed a beaker on a balance and the mass of the beaker was 132.5 grams.  The student then added some iron to the beaker, the mass increased to 147.3 grams.  How many moles of iron did the student have? (enter your answer with 3 decimal places and no units, the understood unit is mole)

45.0 mL of 6.0M HCl (aq) was placed placed into an empty fla…

45.0 mL of 6.0M HCl (aq) was placed placed into an empty flask which has the mass of 50.000 grams.  Total mass became 95.020 grams.  After adding 2.000 gram of CaCO3 to the open flask containing HCl (aq), a reaction was observed with gas bubbles.  After the reaction comes to completion, the total mass of the flask and products became 96.148 grams.  What’s the mass of the gas produced by this reaction? Mark your answer next to words “Final answer is”.  You must follow significant figure rules.  Show your work here to receive any partial credit. 

Provide the probability in terms of a decimal or percent. [7…

Provide the probability in terms of a decimal or percent. [7 Points Each] 1) Assume that blood pressure readings are normally distributed with a mean of 120 and a standard deviation of 8. If 100 people are randomly selected, find the probability that their mean blood pressure will be greater than 122.   2) Assume that the salaries of elementary school teachers in the United States are normally distributed with a mean of $32,000 and a standard deviation of $3000. If 100 teachers are randomly selected, find the probability that their mean salary is less than $32,500.