Agroup of students were asked to identify three white powders. the students use the physical and chemical properties to identify the powders. they computed the density of each powder. they check to see if any dissolved in water. one of the powders did not dissolve in water and they thought it was corn starch. they knew that cornstarch felt slippery and reacted with iodine. the students put a few drops of iodine on each white powder. one powder turned black it was definitely cornstarch. another powder, baking soda reacted with vinegar. it first and the test tube got hot. which of these is an observed chemical property? a. color of powders b. density of powders c. powder dissolved in water d. powder reacts with vinegar? me

D. Powder react with vinegar

Explanation: All the other choice is physical change. Choice A is a change of color but it doesn’t change the properties. Choice B is an example of physical change which is simply for measurements therefore doesn’t affect the properties. Choice C is also physical change because solubility and dissolve are type of physical change leaving us with the last choice which is choice D. Since the powder reacts with the vinegar it changes the property of the powder.

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.