What mineral is not scratched by a fingernail, but is scratched by a copper penny?

Nuclear fusion in the sun involves hydrogen (H) atoms combining to form helium (He). A student claims that since the atmosphere contains hydrogen, any fusion reaction on Earth would result in an uncontrolled chain reaction.

How many moles of methane are required to produce 22g co2 after combustion

whwn placed in solution an inorganic substance dissociates completlt forming hydtogen ions and anions

When magnesium-28 undergoes beta decay, what is the identity and mass number of the nucleus formed?

An example of a scientific law is the law of conservation of mass, which states that matter is neither created nor destroyed in a chemical reaction.

A sample of NO2 in a 1550 mL metal cylinder at 70.26 kPa has its temperature changed from 480oC to - 237oC while its volume is simultaneously changed by a piston to 5114 mL. What is the final pressure in kPa?

How many grams of methane gas (CH4) are in a 15.8-liter sample at 1.2 atmospheres and 27°C? Show all work used to solve this problem

Oxygen forms a number of compounds with sulfur, many of which are quite reactive. One such compound is 57.20 % by mass S. Calculate the number of grams of oxygen present in a sample of this compound that contains 50.00 grams of S.

What is meant by "pressure of the atmosphere?" What causes this pressure?

A substance is analyzed and found to contain 85.7% carbon and 14.3% hydrogen by weight. A gaseous sample of the substance is found to have a density of 1.87 g/L, and 1 mol of it occupies a volume of 22.4 L.