Which answer would provide the most detailed and accurate description of the observations for this reaction?Group of answer choicesThe test tube contains both a white, cloudy liquid and a clear, colorless liquid.The test tube contains a white liquid and a clear, colorless solid.The test tube contains a white solid floating in a clear, colorless liquid.The test tube contains a clear, colorless liquid with a white solid that has sunk to the bottom.

According to the pre-lab presentation, which of the following is a reason for a "false positive" conclusion that a chemical reaction occurred in the test tube?Group of answer choicesTwo clear colorless liquids are combined and produce no visual change (still a clear colorless liquid) when the test tube is agitated.Bubbles are observed after the test tube is agitated.An odor is generated when the test tube is agitated.A red color in the test tube changes to a blue color after the test tube is agitated.

For which of the following cases is there a clear indication that a chemical reaction is taking place?Case 1:  Two clear, colorless liquids at 19.5 degrees Celsius are combined in a test tube.  A few seconds later, the contents of the test tube appear to be a clear, colorless liquid with a temperature of 19.8 degrees Celsius.Case 2:  Two clear, colorless liquids at 24.3 degrees Celsius are combined in a test tube.  A few seconds later, the contents of the test tube appear to be a clear, colorless liquid with a temperature of 32.9 degrees Celsius.

A student heated a blue copper sulfate crystal in a test tube. After a few minutes, she observed that the crystal turned white and the inside of the test tube was covered with a thin film of water. The water inside the test tube most likely __.Multiple choice question.condensed from the air around the test tubecame from the blue copper sulfate crystal, which is a hydrateseeped through the sides of the test tubewas left from cleaning the test tube the night before

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

15 An anhydrous white salt, Z, is heated strongly for 30 minutes. A mixture of gases is given off. Thesolid remaining in the test-tube is then dissolved in a small volume of dilute hydrochloric acid. Theaddition of a few drops of dilute sulfuric acid to the test-tube causes a white precipitate to form.Which substance could be Z?A barium carbonateB barium nitrateC magnesium carbonateD magnesium nitrate