Dihydrogen (hydrogen gas) is highly flammable and will burn at concentrations of 4% or more H2 in air. The enthalpy of combustion for hydrogen is −286 kJ/mol; it burns according to the following balanced equation. : 2 H2(g) + O2(g) → 2 H2O(l) + 572 kJ (286 kJ/mol) When mixed with oxygen across a wide range of proportions, hydrogen explodes upon ignition. Hydrogen burns violently in air. It ignites automatically at a temperature of 560 °C. Pure hydrogen-oxygen flames burn in the ultraviolet color range and are nearly invisible to the naked eye, as illustrated by the faintness of flame from the main Space Shuttle engines (as opposed to the easily visible flames from the SRBs). Thus it requires a flame detector to detect if a hydrogen leak is burning. The explosion of the Hindenburg airship was an infamous case of hydrogen combustion; the cause is debated, but combustible materials in the ship's skin were responsible for the coloring of the flames. Another characteristic of hydrogen fires is that the flames tend to ascend rapidly with the gas in air, as illustrated by the Hindenburg flames, causing less damage than hydrocarbon fires. Two-thirds of the Hindenburg passengers survived the fire, and many of the deaths which occurred were from falling or from diesel fuel burns. H2 reacts directly with other oxidizing elements. A violent and spontaneous reaction can occur at room temperature with chlorine and fluorine, forming the corresponding hydrogen halides: hydrogen chloride and hydrogen fluoride
Yes, when hydrogen explodes it produces water.
No. Oxygen gas relights flames. Hydrogen gas will explode in the presence of fire, giving a 'squeaky pop'
Concentration of hydrogen ions in a solution is called: Acid concentration and pH = - log10(hydrogen ions concentration, in mol/l)
Yes. Hydrogen sulfide is extremely flammable.
Liquid Nitrogen in a water bottle will explode because of pressure build up. Liquid nitrogen vaporizes rather quickly and when it transitions from liquid to gas, the pressure increases if kept at the same volume. Think of boiling water in a closed container. It is similar to that but liquid nitrogen evaporates at much lower temperature, it will explode at room temperature. Let's say you submerged this water bottle below the boiling point of liquid nitrogen and put liquid nitrogen in the bottle, the bottle will not explode. It is a mechanical explosion (simple transfer of forces) not a chemical explosion like with hydrogen where hydrogen gas ignites.
A contact with hydrogen or organic compounds at a high temperature.
A contact with hydrogen or organic compounds at a high temperature.
Hydrogen can be made to explode in two different ways. The most usual way would be by combustion with oxygen, but that requires ignition. However, if you have liquid hydrogen you could make it explode by heating it, even in the absence of oxygen, in exactly the same way that water in a sealed container will explode if you heat it to the boiling point. Liquid hydrogen, of course, has a much lower boiling point than water does, and therefore would require less heating to make it explode. If it is not kept cooled, it will explode even at room temperature.
Yes, when hydrogen explodes it produces water.
No. Oxygen gas relights flames. Hydrogen gas will explode in the presence of fire, giving a 'squeaky pop'
Concentration of hydrogen ions in a solution is called: Acid concentration and pH = - log10(hydrogen ions concentration, in mol/l)
Bases have a low concentration of hydrogen ions. In contrast, acids have a high concentration of hydrogen ions.
yes, because temperature effects the concentration of hydrogen ions, which is what in turn effects pH values
Yes. Hydrogen sulfide is extremely flammable.
pH is the negative logarithm of the hydrogen ion concentration; so an increase in hydrogen ion concentration give a reduction in pH. A reduction in hydrogen ion concentration causes an increase in pH.
Generally this concentration is 36.5 %. However cocentrations up to just over 40% are possible but require special pressure and cool temperature conditions because the vapor pressure of the hydrogen chloride (which is dissolved into water to make hydrochloric acid) is high enough to cause evaporation of the hydrogen chloride out of the solution which then reduces the concentration unless you have the pressure and temperature conditions.
yes, because temperature effects the concentration of hydrogen ions, which is what in turn effects pH values