Is limestone a mixture or a pure substance

An early method of producing hydrogen gas was passing steam through red-hot iron pipes according to the reaction 3 Fe (s) + 4 H2O (g) → Fe3O4 (g) + 4 H2 (g) How many liters of hydrogen gas at STP can be created by reacting 15.3 g of iron?

In a different experiment, the student uses a calorimeter which is perfectly insulated. She fills the calorimeter with 100.0 g of 25.00°C dilute HCl solution and adds 0.594 g Mg metal (24.3 g/mol). The final temperature of the apparatus comes to 41.

How many electrons in an atom could have n = 2, l = 1, ml = 0?

Why can scientists get energy from plants

assume you have a 500 g sample of a radioactive isotope with a half-life of 100 years. fill in the table showing how many grams of material will remain after the indicated time has passed.

The frequency of a given region of the electromagnetic spectrum is more than 3 x 1019 HZ. Note that the speed of light is 2.998 x 108 m/s. Which waves are found in this region? A. gamma rays B. visible light C. microwaves D. radio waves E. x-rays

A farmer uses water to irrigate his potato crops. Which roles of water does this examplify

How was helium first discovered?

When is alpha particle emission most likely to occur? A. When the nucleus has more than 83 protons. B. When the ratio of neutrons to protons in the nucleus is too high to be stable. C. When the nucleus has a mass of more than 83 amu. D.

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.