Hydrogen gas burns in air. Exposing hydrogen to a flame causes it to react with oxygen, forming water. A small flame put into a test tube of hydrogen gas will burn it quickly with a loud popping sound. This is known as a 'pop' test. Propose how a pop test would be useful for detecting if a chemical change has occured.

Describe how to test the gas to show that it is hydrogen

This question is about tests for some elements and compounds.(a) What is the test for hydrogen?(b) The diagram shows hydrogen burning in air, and how some of the gases passing throughthe apparatus are collected and tested.A colourless liquid collects in the U- shaped tube and the limewater turns cloudy very slowly.(i) Describe a chemical test to show that the colorless liquid contains water.testresult(ii) Describe a physical test to show that the colourless liquid is pure water.testresult

Hydrogen gas burns in air with a

A scientist obtains a mixture of methane and oxygen in a closed opaque vessel. She knows that a mixture of methane and oxygen is a clear gas. She then follows these steps:Light a fuse to provide a spark inside of the vessel.Carefully extract the gas out the vessel directly into a large sealed test tube.Observe the gas in the test tube.Determine whether or not a chemical reaction occurred after lighting the fuse.The scientist sees that the gas in the test tube is still a clear gas. How can the scientist determine whether or not a chemical reaction occurred in the test tube? A. by observing the color of the gases in the test tube and comparing them to those of methane and oxygen B. by testing the boiling points of the gases in the test tube and comparing them to those of methane and oxygen C. by determining whether or not a phase change occurred because the fuse was sparked D. by determining whether or not mass of matter was gained because the fuse was sparked

A student found this information about hydrogen.(a) (i) The student repeated Boyle’s experiment using iron and dilute sulfuric acidState two observations that he could have made1.2.(iii) Complete the word equation for this reaction.Iron + sulfuric acid → +(b) Balance the equation for the complete combustion of hydrogen.H2 + O2 → H2O(c) To show that the liquid produced by burning hydrogen was pure water, a student carried out achemical test and a physical test.(i) The chemical test involves adding a few drops of the liquid to a sample of anhydrous copper(II) sulfate. State the colour change observed.Initial colourFinal colour(ii) Place a cross (  ) in one box to show the formula of the compound formed in this chemical test. A Cu(OH ) 2 B CuSO4 C CuSO4H2O D CuSO4 . 5H2O(iii) The physical test involved measuring a property of the liquid.State a suitable physical property and give the value for pure water.Physical propertyValue(c) (i) suggest what property of hydrogen makes it suitable for filling balloons.(iii) Helium is now used instead of hydrogen to fill balloons.State the property of helium that makes it more suitable than hydrogen for filling balloons.(d) Write an equation, including state symbols, to show the process that occurs when hydrogen isliquefied.Ammonium chloride contains oppositely charged ions(a) State the formula of each ionPositive ionNegative ion(b) (i) Describe a chemical test to show that a substance contains ammonium ions.(ii) describe a chemical test to show that a substance contains chloride ions.(c) Ammonium chloride decomposes when heated:NH4CI(s) ⇄ NH3(g) + HCI(g)What does the ⇄ symbol indicate about the reaction?(d) The reaction between ammonia and hydrogen chloride can be used to illustrate diffusion withthe following apparatus.After a few minutes, a white solid appears inside the tube(i) Identify the white solid(ii) What does the diagram show about the speed of the ammonia molecules compared to thespeed of the hydrogen chloride molecules?(e) State the main hazard when using concentrated hydrochloric acid in the experiment in (d)suggest one precaution you could use to minimise this hazard.HazardPrecaution