CHEM問題 20 點 神人plx

Which of the following statements concerning chlorine water is correct?
1) It has no observable change when it's added to NaCl solution

The statement is correct.


Ionic compounds are formed by metal and non-metal only.
Calcium carbonate is ionic compuond.
ans 話only one statement 岩,,,點解??

The first statement is incorrect. Ammonium compounds are exceptions to the statement. For example, ammonium chloride (NH4Cl containing NH4^+ and Cl^- ions) is an ionic compound which are formed by non-metals (N, H and Cl) only.

The second statement is correct.


Which of the following statements concerning one mole of CO2 is correct?
1)It contains 6.02 x 10^23 of atoms
點解唔岩?

No. of moles of CO2 molecules = 1 mol
No. of CO2 molecules = 6.02 x 10²³
Each CO2 molecule contains 3 atoms (1 C atom + 2 O atoms).
No. of atoms = (6.02 x 10²³) x 3 ≠ 6.02 x 10²³


Acid salt solution is acidic.
Sodium hydrogensulphate is an acid salt
ans話only one statement 岩,,,點解??

The second statement is correct.

The first statement is incorrect. Most acid salt solutions are acid, but NOT ALL. For example, NaHCO3 is an acidic salt but its solution is slightly alkaline (0.5 M NaHCO3 has a pH 8.31 at room temperature).


同埋我想問Hydrogen atom 會有 proton, electron 定neuton
hydrogen ion 會有 proton electron 定neutron

A hydrogen atom contains 1 proton and 1 electron only.
A hydrogen ion contains 1 proton only.

Which of the following statements concerning one mole of CO2 is correct?
1)It contains 6.02 x 10^23 of atoms
點解唔岩?
co2有3個atom,所以1mole co2有3mole的atom, 所以應該係3x6.02x10^23

同埋我想問Hydrogen atom 會有 proton electron 定neuton
hydrogen ion 會有 proton electron 定neutron

hydrogen atom有proton同electron,但冇neutron
hydrogen ion得proton,冇electron同neutron

對唔住呀....其他果3題我都唔識.....
不過e題我都可以估一下,唔好盡信lo,估only
Acidic salt solution is acidic.
Sodium hydrogensulphate is an acid salt
ans話only one statement 岩,,,點解??

Sodium hydrogensulphate is an acid salt
e句可能錯,
你可以諗下sodium hydrogencarbonate,佢好似係alkali因為佢react with acid to form salt and water(neutralization)......
我估Sodium hydrogensulphate都係同樣道理
(講多次,估姐....未必岩)