The question is incomplete, the complete question is;
The compound magnesium phosphate has the chemical formula Mg3(PO4)2. In this compound, phosphorus and oxygen act together as one charged particle, which is connected to magnesium, the other charged particle. What does the 2 mean in the formula 5Mg3(PO4)2? A. There are two elements in magnesium phosphate. B. There are two molecules of magnesium phosphate. C. There are two magnesium ions in a molecule of magnesium phosphate. D. There are two phosphate ions in a molecule of magnesium phosphate.
Answer:
There are two phosphate ions in a molecule of magnesium phosphate.
Explanation:
The compound magnesium phosphate is an ionic compound. Ionic compounds always consists of two ions, a positive ion and a negative ion.
In this case, the positive ion is Mg^2+ while the negative ion is PO4^3-.
The subscript, 2 after the formula of the phosphate ion means that there are two phosphate ions in each formula unit of magnesium phosphate.
In 2Cr2O7 there’s 2 items; Cr and O
The energy stored by a system of capacitors is given by

where Ceq is the equivalent capacitance of the system, and V is the voltage applied.
In the formula, we can see there is a direct proportionality between U and C. This means that if we want to increase the energy stored by 4 times, we have to increase C by 4 times, if we keep the same voltage.
Calling

the capacitance of the original capacitor, we can solve the problem by asking that, adding a new capacitor with

, the new equivalent capacitance of the system

must be equal to

. If we add the new capacitance X in parallel, the equivalent capacitance of the new system is the sum of the two capacitance

and since Ceq must be equal to 4 C1, we can write

from which we find
Answer:
what do you need help with? Like which type of print each image is?
Explanation: