Which equation obeys the law of conservation of mass? H2 (g) + O2 (g) → H2O (g) H2 (g) + O2 (g) → H2O (g) + 4He (g) 2H2 (g) + O2 (g) → 2H2O (g) H2 (g) → H2O (g) H2 (g) + O2 (g) → 2H2O (g)

Which of the following produces a chemical change?

How many moles are present in 454 grams of CO2? A. 10.31 mol B. 4.54 mol C. 37.83 mol D. 14.18 mol E. 1.3 mol

The periodic table was arranged so that properties could be predicted for elements, just by looking at their position in relation to other elements. Consider two of the group 2 elements, Magnesium and Strontium.

Fill in the blank. are pure substances that cannot be broken down into a simpler form. are units of two or more atoms. are the smallest possible particles of an element. are pure substances made of two or more atoms of different elements.

Suppose the total volume of sand on the beach is 1,278m. What will the volume be after 24 hours of erosion?

A group of organisms that breed and produce offspring that can breed. A. Species B. ecosystem C. Biodiversity

What is the molality of a solution containing 100 grams of glucose (C6H12O6, molar mass = 180 g/mol) dissolved in 2.5 kg of water? 0.22 m 72 m 7200 m 40 m

A battery is constructed based on the oxidation of magnesium and the reduction of cu2+. the initial concentrations of mg2 + and cu2 + are 1.2*10-4 m and 1.44 m, respectively, in 1.0-liter half-cells. how long can the battery deliver 5.

A buffer solution is made that is 0.417 M in and 0.417 M in. If for is, what is the pH of the buffer solution? pH = Write the net ionic equation for the reaction that occurs when 0.120 mol is added to 1.00 L of the buffer solution.

BaCl2 (aq) + AgNO3 (aq) → Express your answer as a chemical equation. Enter noreaction if no precipitate is formed.