Questions about the quantity of a chemical substance, several questions about the quantity of a subs

The gas is magnesium carbonate and sodium bicarbonate, and the precipitate is mg(oh)2, because of the excess sodium hydroxide, the amphoterics of aluminum make it not precipitate, so, according to the precipitation, the mass of mgCO3 can be found,:

mgco3 ～ mg(oh)2 ～co2

84g 58g

m vm=21g v=

That is, the volume of gas released by sodium bicarbonate and hydrochloric acid is.

Then: NaHCO3 CO2

84gm1m1=21g

Then the mass of Al(OH)3 is 81g-21g-21g=39gNAHco3, and the amount of Al(Oh)3 is 1:2

Because both MgCO3 and NaHCO3 can only produce 1 CO2, so N(mgCO3)+N(NaHCO3)=

And because there is an excess of NaOH, there is no Al(Oh)3, i.e., Mg(OH)2, and we can get N(Mg2+) = i.e., MgCO3=21g, and in the same way, N(NaHCO3) = m(NaHCO3)= then Al(Oh)3=39g N(Al(OH)3) = So, N(NaHCO3) n(Al(OH)3)=1 2

1:2hgo=2hg+o2

2kclo3=2kcl+3o2

2kmno4=k2mno4+mno2+o2nh3hco3=nh3+co2+h2o

The mass ratio of the blind reactant to the gas produced by the same amount of material is 1:1 2, so the largest volume of gas released is d

2: The amount of gas added after turpentine absorption is O3, the volume is so O2 gas volume, and the volume fraction of O2 is 3 4

3: Ammonium sulfate is (NH4)2SO4

The number of nitrogen atoms in the Hub.

Ammonium nitrate is NH4NO3, and 8g is Mopaosong.

The number of nitrogen atoms is.

Ammonia bicarbonate is NH4HCO3, and the number of nitrogen atoms is.

d is not clearly written.

4: Sulfur trioxide is solid.

The amount of sulfur dioxide substance is the number of sulfur atoms.

Therefore, the required sulfur trioxide is also, 24g of sulfur trioxide is needed!

100ml, hydrochloric acid solution in the manuscript loose contains a mask with HCl.

The quantity that the substance is noisy.

Why? hcl+naoh=nacl+h2o

1molHCl requires 1molNaOH, so the amount of substance that requires NaOH m(mg) = 24

m(koh)=39+16+1=56

naol something, haven't seen it.

Solution: Because 2Cu+S=(Heating)=Cu2S, the valency increases by 1, and under certain conditions, the amount of copper is , and the number of transferred electrons is when it reacts with excess sulfur.

At room temperature, the number of solute molecules contained in 1L of 1mol L of CH3COOH solution is less than Na because CH3COOH is a weak electrolyte, and it is partially ionized as CH3COO- and H+ in the solution, so the number of CH3COOH molecules contained, that is, the number of solute molecules contained is less than Na.

Under certain conditions, copper reacts with excess sulfur, and the number of electrons transferred is . This statement is wrong, why? What's wrong**?

2Cu + S = Heating = Cu2S

A copper loses an electron and becomes a +1 valence cuprous ion, so it should be at room temperature, 1L of 1mol L of CH3COOH solution, the number of solute molecules contained is less than NaThis statement is true, why is it less than NA?

CH3COOH is a weak electrolyte that partially ionizes in solution, so the number of solute molecules is less than 1NA

Because copper reacts with sulfur to form cuprous sulfide, the amount of copper atom = transfer electrons, so it is wrong;

The amount of substances containing acetic acid molecules in 1 L of 1mol L of CH3COOH solution is = 1 L * 1mol L = 1 mol

However, because acetic acid is a weak electrolyte, a part of the ionization in the aqueous solution generates acetate ions and hydrogen ions, so the number of solute molecules contained in it is less than na

If the ammonium salt is coheated with the filtrate, the gas will be generated. "The gas is NH3, which indicates that the amount of hydroxide ions in the filtrate is moles. [Regardless of the dissolution of ammonia] that is, M(OH)2·XH2O is; "The action of filtrate and acid does not produce gas" means that the sodium carbonate is all reacted, we let it be ymol, then the generated MCO3 precipitate is also ymol, the mass is grams, and my+60y=the relative atomic mass of the table pants indicates m]; After high temperature burning, it becomes ymolmo, and the mass is, my+16y=; joint solution, get y=; Substitution or get m=137 [ba, match!]

The relative atomic mass of m is 137; According to the solution of "the mixture of m(oh)2·xh2o and sodium carbonate", the chemical formula of the hydrated crystal of x=8,m hydroxide is ba(oh)2·8h2o

1。The ratio of the mass of each atom in a molecule is the ratio of the number of atoms that make up the molecule. For example, the ratio of the amount of H atom to O atom matter in the H2O molecule is 2:

12。In the same way for ionic compounds, the ratio of the amount of matter of each ion is also the ratio of the number of ions that make up it, but it has no significance to compare it with the amount of matter of the whole compound. For example, the CaCl2 of calcium chloride 1mol, the chloride ion is 2mol, and the ratio of the amount of calcium chloride substance is 2:

13。A molecule is generally composed of multiple atoms, so the sum of the substances of the atoms is usually greater than the amount of the molecules. For example, if the H2O molecule has 1mol, the hydrogen atom has 2mol, and the oxygen atom has 1mol, then the sum of the substances of each atom is greater than 1mol.

1. The amount of interatomic matter in a molecule is determined by the subscript.

2. The amount of the ionic substance in the molecule should be equal to the sum of the corner marks multiplied by the amount of the molecule's substance.

3. This problem is not necessarily because it is necessary to distinguish between the molecular formula of monoatomic molecules and polyatomic molecules, and the monoatoms should be equal, such as noble gases. In the case of polyatomics, it should be the sum of the corner marks

Solution mass = g;

The mass fraction of magnesium ions is equivalent to 24% magnesium sulfate;

Solute magnesium sulfate: 600 24% 120 = mol;

Solvent water: 600 76% 18 = mol;

The ratio of the amount of solute to solvent substance is::190

The mass fraction of sulfate ions is 24%.

There is 500ml of magnesium sulfate solution, and its density is, so the mass fraction of the mass of 600g magnesium ions is, so the magnesium mass is.

mgso4---mg

xx=144g

So the mass fraction is 144 600 = 24%.

Because of 144 g of solute, the amount of matter is 144 120 = because water 600-144 = 456 g

456/18=76/3mol

So the answer is.

= m v m solvent = v = m (mg2+) = 600 * m (mg2+) = 24 m (mgSO4) = 120 m (mg2+) m (mgSO4) = m (mg2+) m (mgSO4) so m (mgSO4) = 144g

mSolute mSolvent = 144 (600-144) = 18 57