The mass fraction of calcium carbonate in limestone was determined

From the comparison of the data of experiment 1 and experiment 2, it can be seen that every 20g of dilute hydrochloric acid reacts with 16g-11g of 5g (or 11g-6g of 5g) of calcium carbonate.

However, in the third experiment, 20g of dilute hydrochloric acid was added, but the reduced mass was less than 5g, which showed that the calcium carbonate reaction was complete, that is to say, there was no calcium carbonate in the remaining solids, and hydrochloric acid would not be reduced again.

So n in the fourth experiment is equal to.

Mass of calcium carbonate in the sample:

Mass fraction of calcium carbonate in the sample:

The first addition of hydrochloric acid reacts with 16-11 = 5 grams of limestone;

The second addition of hydrochloric acid reacts with 11-6 = 5 grams of limestone;

The third addition of hydrochloric acid only reacts with grams of limestone, indicating that the limestone has completely reacted, and the remaining grams are impurities.

1) The value of n in the table above is grams.

2) The mass fraction of calcium carbonate in the sample (

3) Find the mass fraction of solutes in hydrochloric acid:

Let 5 grams of limestone react with x grams of hydrochloric acid.

CaCO3+2HCl=CaCl2+CO2+H2O5---xx=g, so the mass fraction of hydrochloric acid =

caco3+2hcl=cacl2+h2o+co24x y

x=100*

y=73*mass fraction of solute in dilute hydrochloric acid=

Know the quality of limestone, use it and carbon dioxide.

reaction, listing the equations.

Calculate the amount of calcium carbonate participating in the reaction, and then use sodium carbonate.

Divide the mass by the limestone mass.

Then carbon dioxide carbonized lime milk is introduced to form calcium carbonate precipitation, and finally dehydrated, dried and crushed to prepare. Or start with sodium carbonate and calcium chloride.

Perform metathesis reactions.

Calcium carbonate precipitates are generated, which are then prepared by dehydration, drying and crushing. Because the sedimentation volume of light calcium carbonate is larger than that of specific calcium carbonate, it is called light calcium carbonate.

Substituting the mass of the gas produced.

The molecular formula of calcium carbonate is CaCO3 and the relative molecular weight is. Among them, calcium oxide (CAO) accounts for and carbon dioxide (CO2) accounts for it. Calcium carbonate is an inorganic compound that is the main component of limestone, or limestone for short.

Calcium carbonate is mainly used

Rubber industry: Calcium carbonate is one of the most widely used fillers in the rubber industry. Calcium carbonate is heavily filled in rubber, which can increase the volume of its products and save expensive natural rubber, thereby significantly reducing costs.

Calcium carbonate is added to rubber to obtain higher tensile strength, tear strength and abrasion resistance than pure rubber vulcanos.

Calcium carbonate can play a skeleton role in plastic products, which has a great effect on the dimensional stability of plastic products, and can also improve the hardness of products, and improve the surface gloss and surface flatness of products. Since the whiteness of calcium carbonate is more than 90%, it also replaces expensive white pigments.

Paint industry: The amount of calcium carbonate in the paint industry is also large, such as more than 30% in thick paint.

Water-based coating industry: calcium carbonate is more widely used in the water-based coating industry, which can make the coating non-sedimentation, easy to disperse, good gloss and other characteristics, and the dosage in water-based paint is 20-60%.

The formula of calcium carbonate caCO3 is 40 + 12 + 48 = 100, in which the calcium segment is 40 100 100% = 40%, and the mass fraction of calcium carbonate in limestone is 80%, so the calcium in this limestone grip comes from calcium carbonate, and the mass fraction of calcium is 80% 40% = 32%.

Let the mass of calcium carbonate in the original sample be X, and the mass of CaCl2 generated is YcaCO3+2HCl=CaCl2+H2O+CO2 x Y G

Easy to get x=10 g

So the mass fraction of calcium carbonate in the limestone sample is 10

y= g so the mass fraction of solute in the solution obtained after the reaction is.

Answer: The mass of calcium carbonate in the original sample is 10g, and the mass fraction of the solute in the solution obtained after the reaction is, 2,1 The mass fraction of calcium carbonate in the limestone sample 2 The mass fraction of the solute in the solution obtained after the reverse masking.

Take a limestone sample and add dilute hydrochloric acid with a certain mass fraction macro. After a full reaction, carbon dioxide gas is collected (impurities in limestone are neither soluble in water nor react with dilute hydrochloric acid, please explain in full!)

The question here depends on the data, the answer is in the test data, from the third and fourth times you can know that it is no longer reacting with hydrochloric acid, so 8g of impurities in this sample, you then the second m value =

What is the mass fraction of calcium in the carbonic acid plexus in the sample?

What should be the value of the number of m in the early Zheng Qipin? m=

1. Comparison.

The second and third sets of data are easy to know: there is a surplus of ore in the third and fourth tests 2, and the acid can be known in the third test has been completed, so adding more calcium carbonate will not change the quality of carbon dioxide generated, and the value of m is easy to know:

3. The calcium carbonate in the first and second experiments is completely reactive, so the first or second experimental data can be selected to calculate.

m (calcium carbonate) = 100 x = 4

The mass fraction of calcium carbonate in limestone is 4 5 = 80%.

Note: Is there an error in the data from the second trial? I think it should be changed to to be in line with the topic. ）

co2100+

Mass fraction of calcium carbonate in calcium carbonate limestone = 10 * 100% 12 =

The question here depends on the data, the answer is in the test data, from the third and fourth times you can know that it is no longer reacting with hydrochloric acid, so 8g of impurities in this sample, you then the second m value =

What is the mass fraction of calcium carbonate in the sample?

What should be the value of m in the sample? m=

According to the meaning of the title: the step of the experiment is to divide 200g of dilute hydrochloric acid into 4 points equally, that is, 50g per portion, and then add samples separately for testing.

1) In which reactions is there any ore leftover?

The chemical reaction equation is: 2HCl+CaCO3=CaCl2+H2O+CO2

Since the molecular weights of CaCO3 and CO2 are 100 and 44 respectively, that is, 3100 grams of pure CaCO2 are required to generate 44 grams of CO2, according to the calculation of the chemical reaction equation:

The first 5 grams of sample to produce grams of CO2 consumes 4 grams of pure CaCO3, and this step alone does not determine whether the reflection is complete. (At this time, it is not possible to tell whether HCl in dilute hydrochloric acid has been depleted.) ）

The second 10 g sample yields 8 grams of pure CaCO3 to produce grams of CO2. (At this time, it is still not possible to tell whether the HCl in dilute hydrochloric acid has been depleted.) ）

The third 15 g sample yields 10 g of pure CaCO3 to produce 10 g of pure CaCO3. Press Section.

The reaction results of the first and second samples are calculated, if the 15 grams sample is completely reacted, grams of CO2 should be generated, indicating that the third sample is not completely reacted, that is, there is a surplus of ore. (Of course, the fourth sample will certainly not be completely reactive, and of course there is a surplus of ore.) ）

Comparing the above data, it can be seen that the first sample and the second sample are completely reactive.

2) What are the values in the table above?

The value of m in the table above:

In fact, the value of m in the table, because the fourth sample has ore left after the reaction, only a part of the ore participates in the chemical reaction, and the third sample is the same as the incomplete reaction. Since the same sample and dilute hydrochloric acid, the value of m should be the same as that of the third sample, equal to grams.

3) Try to calculate the mass fraction of calcium carbonate in this limestone.

Since the third sample has a surplus at the end of the reaction, the HCl in dilute hydrochloric acid has been depleted. According to the chemical reaction equation, grams of CO2 need to be consumed, and 10 grams of pure CaCO3 should be consumed. In this question.

Although the first and second samples were completely reacted, the HCl in dilute hydrochloric acid was not consumed after the reaction. In the third sample, although the HCl in dilute hydrochloric acid has been consumed, there is a surplus in the sample, that is, none of the reactions are exactly complete between the sample and the dilute hydrochloric acid. Therefore, the mass fraction of calcium carbonate in the sample cannot be judged, and only an approximate range can be stated, which is more than 80%.

Note: I am a laboratory technician in a cement plant, and I know how to determine the caCO3 content in limestone, and it is impossible to know it so accurately from a simple chemical reaction. It is necessary to pass through a series of chemical reactions in order to accurately determine it.

Hum! Now that there is the Internet, you students don't use your brains to do your homework.