Author: Anonymous

When the math expression below is simplified, how many sig figs should the result have?

The density of a certain object is 2.588 g/mL.  You completely submerge the object in a graduated cylinder containing 68.9 mL of water, and observe the water level rise up to 74.3 mL.  What is the mass of the object, in g?

Provide the missing systematic chemical name or chemical formula for the following substances.  Spelling counts.  When entering formulas, all numbers will be assumed to be subscripts.  Include states of matter such as (g) and (aq) ONLY when the state of matter affects the name of the compound.  (1 pt each) Problem # Systematic Chemical Name Chemical Formula A [namea] C2H6 B lead (II) acetate [formulab] C [namec] Ca(NO3)2 

[EXTRA CREDIT] (3 pts possible, question will show as being out of 0 pts) Magnesium nitride reacts with water to produce ammonia and magnesium hydroxide.  How many grams of magnesium hydroxide are produced when 100.00 grams of each reactant are combined, if the percent yield of magensium hydroxide is 76.7%? Show all work, using dimensional analysis, and highlight your answer in a readable background color.

[EXTRA CREDIT] (3 pts possible, question will show as being out of 0 pts) A hotpack is commonly a plastic bag filled with aqueous sodium acetate solution.  Upon shaking the bag, sodium acetate precipitates out of solution, releasing heat in the process to keep your hands warm.  What mass of sodium acetate must precipitate out, in order for the 50.0 mL of water in the hotpack to rise in temperature from 25.0°C to 61.3°C? The heat of crystallization of sodium acetate is -19.7 kJ/mol. Assume the density of water is 0.997 g/mL, and that all heat transfer is between the sodium acetate and the water solvent.  Assume the solution is dilute such that it has the same specific heat capacity as water. Show all work, using dimensional analysis where appropriate, and highlight your answer in a readable background color.

What is the symbol of the element below?  Enter the name using correct case (lowercase/uppercase). chlorine

Given the unbalanced total ionic equation below, which of the following is a spectator that would be removed in the corresponding net ionic equation?   HCl(aq)  +  Ca(OH)2(aq)  –>  CaCl2(aq)  +  H2O(l)

A certain data set has low accuracy, but high precision.  Which of the following statements about error is most consistent with the data set?

How much heat is required to adjust the temperature of 91.2 grams of copper from -32.2°C to 315°C?

What is the molar mass of a gas that has a density of 8.12 g/L at 412°C and 0.750 atm?