What is meant by the negative sign in an answer like"-46.8kJ"? When would you use a positive sign

Can just one measurement be considered precise? Can just one measurement be considered accurate? Explain your answers completely.

Which of the following is equal to 5.3 mm3? 5.3 x 10-6 m3 5.3 x 10-9 m3 5.3 x 10-6 cm3 5.3 x 103 cm3

A 1.33 g sample of water is injected into a closed evacuated 4.81 liter flask at 65°C. What percent (by mass) of the water will be vapor when equilibrium is reached? (the vapor pressure of water at 65°C is 187.5 mmHg)

Rubidium has a mass number of 87 and an atomic number of 37. how many electrons does it have?

A. draw the structure of the tetrahedral intermediate initially-formed in the reaction shown. reactions of esters with

Density is not a physical property of mass. True False

Does skin have a nucleus true or false

Bacteria are only found in decaying matter. A. True B. False

Which is considered a chemical mutagen? tanning beds tobacco X-rays precious metals

Combining 0.380 mol Fe2O3 with excess carbon produced 13.7 g Fe Fe2O3 + 3C → 2Fe + 3CO What is the actual yield of iron in moles? What is the theoretical yield of iron in moles? What is the percent yield?