The half-life of a certain element is 100 days. How many half-lives will it be before only one-fourth of this element remains? 4

50

25

2

A student moves from a region that has short, cool summers and very cold winters to a region that has hot and humid summers but short, cold winters. Both regions are located within which climate? dry highlands temperate marine temperate continental

An extremely soluble salt is added to water, and all of it dissolves. Is it at equilibrium? Explain.

Chlorine gas can be prepared in the laboratory by the reaction of hydrochloric acid with manganese (IV) oxide. 4 HCl (aq) + MnO 2 (s) ⟶ MnCl 2 (aq) + 2 H 2 O (l) + Cl 2 (g) A sample of 37.3 g MnO 2 37.3 g MnO2 is added to a solution containing 50.

The following values are the only allowable energy levels of a hypothetical one-electron atom: E₆ = - 2 x 10⁻¹⁹ J E₅ = - 7 x 10⁻¹⁹ J E₄ = - 11 x 10⁻¹⁹ J E₃ = - 15 x 10⁻¹⁹ J E₂ = - 15 x 10⁻¹⁹ J E₁ = - 15 x 10⁻¹⁹ J (a) If the electron were in the n =

Arrange these 3 reactions according to increasing DS. (1) CH4 (g) H2O (g) - -> CO (g) 3 H2 (g) (2) C (s) O2 (g) - -> CO2 (g) (3) H2O2 (l) - -> H2O (l) 1/2 O2 (g) 1 < 3 < 2 2 < 3 < 1 2 < 1 < 3 3 < 2 < 1 3 < 1 < 2

An electron moved from a lower energy level to a higher energy level. What most likely happened during the transition? A random amount of light was released. A fixed amount of energy was absorbed. A fixed amount of energy was released.

Solid sodium reacts violently with water, producing heat, hydrogen gas, and sodium hydroxide. How many molecules of hydrogen gas are formed when 57.1 grams of sodium are added to water?

The distance from dalton, ga to Dallas, tx is 1308 km. What is the distance in miles

Which will melt faster: ice made from tap water, distilled water, or salt water?

You know that 8.9 moles of solute particles are dissolved in that liquid solution. If the molarity of the solution is 25 M, how many liters of solution do you have?