What is K2Cr2O7 formula?

Answer 1

The chemical formula for potassium dichromate is K2Cr2O7. In this compound, potassium (K) has a +1 charge, and the dichromate ion (Cr2O7) has a -2 charge. The formula represents the combination of two potassium ions and one dichromate ion, which consists of two chromium atoms and seven oxygen atoms.

Answer 2

You can get the Atomic Masses in a Periodic Table: K = 39,1u; Cr = 52,0u; O = 16,0u. Then do de sum: (39,1*2+52*2+16*7) = 294,2u The concept on Formula Mass is similar to the Molecular Mass, but applied to a ionic compound.

Answer 3

The mass of a compound can be determined by summing the mass of the individual parts. For the constituent elements in potassium carbonate:

MK = 39.0983 g/mol

MC = 12.0107 g/mol

MO = 15.9994 g/mol

where Mx designates the molecular mass of element x in grams/mole.

The molecular mass of the compound, then, is:

2(MK) + 1(MC) + 3(MO) = 138.1965 g/mol

This has the correct number of significant figures and to convert to pure grams, we must be given an amount of the substance (usually in moles). Assuming we have 1 mole of the compound, we have

138.1965 g/mol * 1 mol = 138.1965 g

Answer 4

Count the subscripts: 2+2+7=11 atoms per formula unit. Note that if an element does not have a subscript in a formula, it's understood to be 1, and you still have to count it. (For example, H2O means 3 atoms total.)

Answer 5

Like other ionic compounds, K2Cr2O7 does not have true moles. Its gram formula unit mass is 294.18.

Answer 6

230.187 g mol-1but it would not be a stable compound.

Answer 7

The formula mass for K2CO3 is 138.2055 g/mole.

Answer 8

potassium dichromate

Answer 9

still be the same K2Cr2O7

Answer 10

294.185 g mol-1