Answer:1. 5
Explanation: the element is boron and the atomic number is 5
Answer:
a) The wavelength is around 33.8 nm = 3.38*10⁻¹ nm
b) Ultraviolet
Explanation:
a) The energy (E) of a photon is related to its wavelength (λ) by the Planck's equation:
where h = Planck's constant = 6.626*10^-34 Js
c = speed of light = 3*10^8 m/s
E = 3.55*10^6 J/mol
The energy in terms of J/photon is:
Based on eq(1)
\lambda = h\frac{c}{E}=6.626*10^{-34}Js*\frac{3*10^{8}m/s}{5.89*10^{-18}J}=3.38*10^{-8}m
The wavelength is around 33.8 nm = 3.38*10⁻¹ nm
b) In the electromagnetic spectrum the ultraviolet range extends from 390 nm-8.82 nm
The calculated wavelength of 33.8 nm should fall in the UV range.
So if the sum of the enthalpies of the reactants is greater than the products, the reaction will be exothermic. If the products side has a larger enthalpy, the reaction is endothermic. You may wonder why endothermic reactions, which soak up energy or enthalpy from the environment, even happen
Answer:
NH₄CN, NH₄IO₃, Fe(CN)₃, Fe(IO₃)₃
Explanation:
Cations (positively charged ions) can only form ionic bonds with anions (negatively charged ions). However, you can't just simply put one cation and one anion together to form a compound. Each compound needs to been neutral, or have an overall charge of 0. When cations and anions do not have charges that perfectly cancel, you need to modify the amount of each ion in the compound.
1.) NH₄CN
-----> NH₄⁺ and CN⁻
-----> +1 + (-1) = 0
2.) NH₄IO₃
-----> NH₄⁺ and IO₃⁻
-----> +1 + (-1) = 0
3.) Fe(CN)₃
-----> Fe³⁺ and CN⁻
-----> +3 + (-1) + (-1) + (-1) = 0
4.) Fe(IO₃)₃
-----> Fe³⁺ and IO₃⁻
-----> +3 + (-1) + (-1) + (-1) = 0
do you have anymore numbers to add to this problem??
