初中化学经典计算题The classical calculation problems of junior high school chemistry文档格式.docx

1、（2） a day for adults is about 0.15mg, assuming that these are mainly from iodized salt intake of iodized salt, iodine in iodized salt if 20mg 1000g is required, adult daily consumption of iodized salt _.g2. existing impurities in Solid Barium Chloride samples （water insoluble impurities）, take 12.5g

2、 samples into the beaker, then add 39.6g of water to make it fully dissolved, static filtered impurities, 10g filtrate, silver nitrate solution add enough, after complete reaction to precipitate 2.87g. （the calculation is accurate to 0.1%）（1） the mass fraction of solute in filtrate;（2） the mass frac

3、tion of barium chloride in the sample.3 in Jilin Province, some extra-curricular interest groups on a number of samples （iron containing impurities impurities, insoluble in water, no reaction with dilute sulfuric acid） were analyzed, a, B and C three students test were carried out including dilute s

4、ulfuric acid and iron samples only one student for exactly the reaction the experimental data are listed in the following table:ABCBeaker + dilute sulphuric acid 200g, 150g, 150gThe added iron sample 9g, 9g, 14gAfter full reaction, beaker + residue 208.7g, 158.7g, 163.7gPlease analyze the data caref

5、ully and answer the following questions:（1） the dilute sulfuric acid which the classmate took is just a complete reaction to the iron sample;（2） calculate the mass fraction of iron in the sample;（3） calculate exactly the mass fraction of solute in the solution obtained after complete reaction. （the

6、quality of the beaker is 25.4g; the calculation is accurate to 1%）4. Burn 4G sulfur powder in a given mass of oxygen. The experimental data are shown in the following table. Please answer the following questions:The first time or two or three timesO2 mass （g） 346SO2 mass （g） 6（1） in the first experi

7、ment, quality and generation in response to the quality of the S and O2 SO2 ratio is: _.（2） please calculate how much sulfur dioxide is produced by the second experiment（3） fill out the third experiment in the form to produce the quality of sulfur dioxide.Heilongjiang province 5, 10g impure magnesiu

8、m chloride samples （impurities insoluble in water）,50g the water is fully stirred, and the magnesium chloride in the sample is dissolved and filtered （filtrate loss is not negligible）, and the filtrate is reacted with 63.3g sodium hydroxide solution to produce 5.8G white precipitate.Beg: （.） Quality

9、 of Magnesium Oxide in sample.（2） the mass fraction of solute in the solution obtained by the reaction.6, osteoporosis is caused by the bodys calcium deficiency, can be taken calcium supplements to treat. Calcium lactate （CaC6H10O6? 5H2O） is a common calcium supplement, the sale of Calcium Laclate T

10、ablets tablets containing calcium lactate 200mg. an adult calcium deficiency patients take 20 tablets daily Calcium Laclate Tablets agent can achieve the objective of calcium. Calculation: （calculation results retain integer）（1） the mass ratio of each element in calcium lactate.（2） the adult patient

11、s with calcium deficiency should switch to milk （calcium 0.104g in each 100mg milk） to supplement calcium. How many ml of milk should be consumed at least every day?.Jiangsu Province, 7 iron and steel alloy of iron, carbon content in pig iron in 2.0%4.3%, steel carbon content in 0.03%2%. A mass of i

12、ron alloy 10.0g into a conical flask to the conical flask add 100g of dilute H2SO4, just to make the iron alloy iron reaction （carbon insoluble in dilute sulfuric acid; other elements in iron alloy is very low and negligible）, measured to generate H2 volume 4.00L （H2 density in the condition of 0.08

13、80g/L）. According to the calculation, answer: （calculate the result to retain three digits.）（.） Is the iron alloy pig iron or steel?（2） the solute mass fraction of the solution obtained after the reaction.Ningbo City, 8 to 3.1 grams of sodium oxide is added to the quality of m water, after complete

14、reaction, get the solute mass fraction is 16% of the solution, adding 50 grams of hydrochloric acid in the solution, both exactly the reaction. （sodium and water reaction chemical equation: Na2O+H2O=2NaOH）. O:（1） the value of M（2） the mass fraction of solute in hydrochloric acid added.（3） if the sodium hydroxide solution after the reaction becomes 20? C saturated solution, at least to evaporate how many grams of water? （20? C, the sodium solubility is 36 grams）Anhui province 9, the following is the province of some of the calcium plus salt packaging labels on the