A 4.57 g sample of CaCO3 is mixed with a 12.4 g sample of Hydrochloric acid, HCl. How many grams of CaCl2 form from this reaction? Which reactant was limiting? CaCO3 + HCl  H2CO3 + CaCl2

metric time was an attempt to create a standard unit of time based off of 10, but it never took off an is not included in the metric system (si)

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

qualitative observation deals with data that can be observed with our senses: sight, smell, touch, taste, and hearing. they do not involve measurements or numbers. for instance, colors, shapes, and textures of objects are all qualitative observations.