Answer:
CO32−
Explanation:
We have to consider the valencies of the polyatomic ions involved. Recall that it is only a polyatomic ion with a valency of -2 that can form a compound which requires two sodium ions.
When we look closely at the options, we will realize that among all the options, only CO32− has a valency of -2, hence it must be the required answer. In order to be double sure, we put down the ionic reaction equation as follows;
2Na^+(aq) + CO3^2-(aq) ---------> Na2CO3(aq)
Answer:
Manganese
Explanation:
At Mass - No neutrons = Atomic Number = #protons in nucleus
47 - 22 = 25 => At. No. 25 is Manganese (Mn)
Answer:
V = 2600ms⁻¹
Explanation:
Given parameters:
Wavelength(λ) = 13meters
Period (T) = 0.005s
Period(T) is the time it takes for a full cycle of vibration to pass through. It's unit is in seconds (s)
The Velocity of waves is expressed as:
V = fλ
Where f = frequency(s⁻¹)
Frequency of a wave is the number of waves that passes through a point per unit time
f = 1/T
Where T is the period
We can therefore express Velocity of waves as a function of period
V = λ/T
Inputing the parameters, we have:
V = 13m / 0.005s
V = 2600ms⁻¹