How do you know if a chemical reaction has occurred?

Will Stephen hawking be important if he have not developed why or why not

Suppose you have made the following hypothesis: Sharks are most common near coral reefs, because there are more fish there to eat. What prediction could you make based on this hypothesis?

Which of the following are always larger than the neutral atoms from which they are formed? A. positive ions B. negative ions C. cations D. none of the above

An experimental procedure requires 10 ml of acid to be dissolved into a beaker of water. An additional 5 ml of acid is added to the solution. Which statement best describes the new solution?

What is the pressure in mm of Hg, of a gas mixture that contains 1g of H2, and 8.0 g of Ar in a 3.0 L container at 27°C.

Why is photosynthesis so important to plants, and can't animals use it?

One way the government of Kim Jong-il controls the lives of the people who live in North Korea is by a. requiring every citizen to vote. b. controlling information its people receive from the outside world. c. enforcing free trade with other nations.

Give reasons 1) copper utensils and sheets become blackish after some days

Predict the spontaneity of a reaction (and the temperature dependence of the spontaneity) for each possible combination of signs for? H and? S (for the system).

At 29°C, Kp = 5.3 ✕ 102 atm-2 for the following reaction. N2 (g) + 3 H2 (g) equilibrium reaction arrow 2 NH3 (g) When a certain partial pressure of NH3 (g) is put into an otherwise empty rigid vessel at 29°C, equilibrium is reached when 55.