What is true about the element calcium(ca, atomic number 20)? choose all that apply. it has 2 valence electrons it has 4 valence electrons it is a nonmetal it is a metal

Abeaker with 2.00×102 ml of an acetic acid buffer with a ph of 5.000 is sitting on a benchtop. the total molarity of acid and conjugate base in this buffer is 0.100 m. a student adds 4.70 ml of a 0.360 m hcl solution to the beaker. how much will the ph change? the pka of acetic acid is 4.740.

Steam reforming of methane ( ch4) produces "synthesis gas," a mixture of carbon monoxide gas and hydrogen gas, which is the starting point for many important industrial chemical syntheses. an industrial chemist studying this reaction fills a 1.5 l flask with 3.5 atm of methane gas and 1.3 atm of water vapor at 43.0°c. he then raises the temperature, and when the mixture has come to equilibrium measures the partial pressure of carbon monoxide gas to be 1 .0 atm. calculate the pressure equilibrium constant for the steam reforming of methane at the final temperature of the mixture. round your answer to 2 significant digits.

If a straight-chain hydrocarbon is a gas at room temperature, how many carbon atoms will it have? a. 6 carbon atoms b. 12 carbon atoms c. 24 carbon atoms d. 3 carbon atoms