Which physical changes are endothermic?

(1) melting and freezing

(2) melting and evaporating

(3) condensation and sublimation

(4) condensation and deposition

What is the density of ammonia gas, nh3, at 31°c and 751 mmhg?

Exactly 5000 mL of air at 223K is warmed and has a new volume of 8.36 liters. What is the new temperature? 100 K 373 K 273 K 123 K

When the temperature of air rises, the amount of water needed for saturation A. increases. B. decreases. C. stays the same. D. increases until it reaches a certain temperature, then drops.

It's Peggy Sue's birthday and she's about to blow out the candles on her cake. Brother Roger stops the party when he shouts: "Look at that! Chemical and physical changes taking places on your birthday cake!

Researchers used a combustion method to analyze a compound used as an antiknock additive in gasoline. A 9.394 mg sample of the compound yielded 31.154 mg of carbon dioxide and 7.977 mg of water in the combustion.

Consider the reaction: 8H2S (g) + 4O2 (g) →8H2O (g) + S8 (g). Δ[H2S]/Δt = - 0.033M/s. Find Δ[O2]/Δt. Δ[H2O]/Δt. Δ[S8]/Δt. Find the rate of the reaction.

At room temperature and pressure what is the volume of one mole of oxygen?

Ibuprofen, a common pain remedy, has an empirical formula of C7H9O and a molar mass of approximately 218.078 grams per mole. What is the molecular formula of ibuprofen?

Copper (cu) is a transition element used in the making of coins. calculate the mass in grams of 0.0420

In 1864, the Solvay process was developed to make soda ash. One step in the process is represented by the balanced equation below.