You must remember that oxidation number of hydrogen in acids is always +1, oxidation number of oxygen in oxides & acids is always -2... metals has always oxidation number on plus!
group NO3 comes from HNO3...and oxidation number of whole acid group is always on minus and equal to the amount of hydrogen atoms in this acid... so oxidation number of NO3 = -1
we have 2 NO3 groups so 2*(-1) = -2 and that is the reason why oxidation number of Fe in this formula must be +2... because sum of all elements always gives 0!
Now we could count of oxidation number for nitrogen... we write HNO3 and start counting from right to left:
3*(-2) from oxygens + 1 from hydrogen = -5
so nitrogen must have +5 oxidation number... because sum all in formula must be 0.
Answer:
5727 years or 5730 (rounded to match 3 sig figs) whichever one your teacher prefers
Explanation:
First Order decay has a half life formula of Half Life = Ln (2) / k = 0.693/K
Half-life = 0.693/k = 0.693/1.21 x10-4 = 5727 years or 5730 (rounded to match 3 sig figs)
This should be correct because if you google the half-life of 14 C it is ~ 5700 years
Moles of X are 0.925 moles.
A mole is a totally vital unit of dimension that chemists use.The mole, symbol mol, is the unit of amount of substance inside the worldwide device of gadgets. the amount quantity of the substance is a measure of how many simple entities of a given substance are in an item or sample. The mole is described as containing exactly 6.02214076×10²³ primary entities
mass of X2O3 = 4 g
so moles = mass/molar mass
molar mass of X2O3 = 2*X + 48 -
Given, that the mass of X = 2.8g
mass of O = 4 - 2.8 = 1.2g
A mole of O = 1.2g/16 = 0.075 mole
∴ mole of X = 1 - 0.075 = 0.925 moles.
Learn more about moles here:-brainly.com/question/15356425
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When they become a solid, as in a solid the particles are packed tightly together and have little space between them, thus at solid state , particles are more ordered.
