Answer is: 3,4
Chemical reaction: HNO₂ + NaOH → NaNO₂ + H₂O.
c₀(HNO₂) = 1,2 M = 1,2 mol/dm³.
c₀(NaNO₂) = 0,8 M = 0,8 mol/dm³.
V₀(HNO₂) = V₀(NaNO₂) = 1 dm³ = 1 L.
c₀(NaOH) = 0,5 M = 0,5 mol/dm³.
n₀(HNO₂)= 1,2 mol/dm³ · 1 dm³ = 1,2 mol.
n₀(NaNO₂) = 0,8 mol/dm³ · 1 dm³ = 0,8 mol.
V(NaOH) = 400 mL · 0,001 dm³/mL = 0,4 dm³.
n₀(NaOH) = c₀(NaOH) · V₀(NaOH).
n₀(NaOH) = 0,5 mol/dm³ · 0,4 dm³ = 0,2 mol.
n(HNO₂) = 1,2 mol - 0,2 mol = 1 mol.
n(NaNO₂) = 0,8 mol + 0,2 mol = 1 mol.
c(HNO₂) = 1 mol ÷ 1,4 dm³ = 0,714 mol/dm³.
c(NaNO₂) = 1 mol ÷ 1,4 dm³ = 0,714 mol/dm³.
pH = pKa + log (c(HNO₂) / c(NaNO₂)).
pH = 3,4 + log (0,714 mol/dm³ / 0,714 mol/dm³) = 3,4.
I think the reaction involved here is a redox reaction in acidic conditions. To balance this type of reaction, we do as follows:
Balance the O atoms in each side by adding H2O on either side.
Balance H atoms in each side by adding H+.
Balance the charges by adding electrons.
Hope this helps.
Okay
Mr (H2O)= 18g
therefore moles of H2O
is 720.8/18= 40.04mol
the ratio of H2 to O2 to H2O is
2 : 1 : 2
so moles of H2 is same as H2O here
H2= 40.04moles
moles of O2 is half
so 40.04 x 0.5
20.02moles
grams of O2 is
its moles into Mr of O2
that's 20.02 x 32 = 640.64g
Answer:
Oxygen
Explanation:
First of all, let's remember that covalent bonds are formed between nonmetal atoms. Given the list of the atoms, calcium is the only metal (it belongs to group 2A, alkaline earth metals). This means calcium doesn't form covalent bonds, it forms ionic bonds. The remaining atoms are all nonmetals and form covalent bonds.
To avoid ambiguity and several choices possible for this problem, we'll assume that we're only talking about diatomic molecules (molecules consisting only of two atoms) in this question.
In covalent bonding, atoms join together to have their valence shells filled, that is, to have octets in their shells (except hydrogen which can only have up to 2 electrons in its shell). Let's look at how many bonds each of these nonmetals will form in a diatomic molecule:
- Chlorine is in group 7A, it has 7 valence electrons, meaning it only needs 1 electron from a covalent bond to have an octet. This implies chlorine will have a single bond.
- Hydrogen is in group 1A, it has 1 valence electron and the maximum it can have in its valence shell is 2 electrons, so it also lacks 1 electron that will be provided by the other atom in a single bond.
- Nitrogen is in group 5A (it has 5 valence electrons). This means it needs 3 more to gain an octet, those would come from a triple bond.
- Carbon is in group 4A (it has 4 valence electrons). It needs 4 more electrons to gain an octet. A quadruple bond would not be possible, the greatest carbon can make is a triple bond in CO having a lone pair remaining on carbon.
- Oxygen is in group 6A (it has 6 valence electrons). It needs 2 more electrons to gain an octet. This implies it would make a double bond to obtain two more electrons from the other atom and acquire an octet.
Answer:
Hello! so this is what I was able to find related to your question.
Explanation:
The oxidation number of this molecule, called a bromate molecule, is -1. It should be correctly written BrO3-. It has this net charge of negative 1 because the bromine has an oxidation number of +5, while oxygen has it's normal oxidation of -2.
