Find the chemical formula of hydrocarbon The experimental results show that the product is CO2 CO and water vapor concentrated H2SO4 alkali lime combustion product ------------ → weight gain of 2.16G ------ → CO2 (1.76g) - ------ → CO2 (0.88g)

Find the chemical formula of hydrocarbon The experimental results show that the product is CO2 CO and water vapor concentrated H2SO4 alkali lime combustion product ------------ → weight gain of 2.16G ------ → CO2 (1.76g) - ------ → CO2 (0.88g)

H2O has 2.16 / 18 = 0.12mol, C has (1.76 + 0.88) / 44 = 0.06, so the hydrocarbon ratio is 1:4, so the chemical formula is CH4

[chemical formula of hydrocarbon] Ethylene and a gaseous hydrocarbon form a mixture, and the volume of oxygen required after complete combustion is 4.5 times that of the mixture, then the gaseous hydrocarbon may be () A C4H8 B C3H8 C C2H6 D C4H4

One molecule of ethylene needs three molecules of oxygen to burn
Now, the volume of oxygen required for the complete combustion of the mixture is 4.5 times that of the mixture, indicating that the complete combustion of one molecule of another gas requires more than 4.5 molecules of oxygen
A C4H8 requires 6 molecules of oxygen
B C3H8 requires 5 molecules of oxygen
C C2H6 requires 3.5 molecular oxygen
D c4h4 requires 5 molecules of oxygen
So choose abd

Take 11.4 g of gasoline sample and burn it fully in oxygen to generate 20.2 g of water and 25.2 g of CO2. Calculate the mass fraction of carbon and hydrogen in gasoline. And why?

It can be seen that gasoline must contain hydrogen and carbon; Therefore, hydrogen element = 2H / H2O * 20.2 = 2.24; Carbon element = C / CO2 * 25.2 = 6.87

Take 11.4 g of gasoline sample and burn it fully in oxygen to produce 16.2 g of water and 35.2 g of carbon dioxide. Calculate the mass fraction of hydrocarbon elements in gasoline sample

The mass fraction of hydrogen in gasoline sample is (16.2g * 2 / 18) / 11.4g * 100% = 15.8%
The mass fraction of carbon element in gasoline sample is (35.2G * 12 / 44) / 11.4g * 100% = 84.2%

At room temperature, a large number of ion groups that may coexist in the following solutions are () A. Add metal magnesium into the solution that can produce H2: Na +, Fe2 +, SO42 -, NO3- B. In the solution containing a large amount of Fe2 +, K +, Mg2 +, ClO -, SO42- C. In the solution that can make Al3 + precipitate: NH4 +, Na +, sio32 -, HCO3- D. C (OH -) = 1 produced by water ionization × In 10-10mol / L solution: Al3 +, SO42 -, NO3 -, Cl-

A. The solution that can produce H2 by adding metal magnesium is an acidic solution. NO3 - ions have strong oxidation and can oxidize Fe2 + in the solution. They must not coexist in a large amount in the solution, so a is wrong; B. In the solution containing a large amount of Fe2 +, ClO - has strong oxidation and can oxidize Fe2 + ions. It must not be a large amount in the solution

The following groups of ions can coexist in large quantities in solution is () A. Cl-    Cu2+    Ag+    K+ B. SO42-    H+    Cl-    Na+ C. Ca2+    K+    CO32-    Cl- D. Ba2+    Cu2+    SO42-    OH-

A. Ag + and Cl - can be combined into silver chloride precipitation and cannot coexist in large quantities, so the option is wrong. B. the four ions cannot be combined into precipitation, gas or water and can coexist in large quantities, so the option is correct. C, Ca2 +, CO32-   The two ions can combine to form calcium carbonate precipitation, which can not coexist in large quantities, so the option is wrong