Increasing order of mass in grams:

1) 2*10^23 atoms of carbon
2) 2g atoms of oxygen
3) 25g of iron
4) 22.4L of carbon dioxide at STP

Explanation:

1) 2*10^23 atoms of carbon:
To determine the mass of 2*10^23 atoms of carbon, we need to know the atomic mass of carbon. The atomic mass of carbon is approximately 12 grams per mole.

To calculate the mass, we can use the Avogadro's number, which states that there are 6.022 * 10^23 atoms in one mole of any substance. Therefore, 1 mole of carbon has a mass of 12 grams.

Using this information, we can calculate the mass of 2*10^23 atoms of carbon as follows:

(2*10^23 atoms of carbon) * (12 grams / 6.022 * 10^23 atoms) = 2 * 12 grams = 24 grams

So, 2*10^23 atoms of carbon have a mass of 24 grams.

2) 2g atoms of oxygen:
It seems there is a mistake in the given statement. Atoms do not have a mass in grams. Atoms have atomic masses measured in atomic mass units (amu). It is not appropriate to compare the mass of atoms with a mass in grams, as they are different units.

3) 25g of iron:
The given statement states that there are 25 grams of iron. Therefore, the mass of iron is 25 grams.

4) 22.4L of carbon dioxide at STP:
To determine the mass of 22.4L of carbon dioxide (CO2) at STP (Standard Temperature and Pressure), we need to know the molar mass of carbon dioxide.

The molar mass of carbon dioxide is calculated by adding up the atomic masses of carbon and oxygen in one molecule of carbon dioxide. The atomic mass of carbon is approximately 12 grams per mole, and the atomic mass of oxygen is approximately 16 grams per mole.

Therefore, the molar mass of carbon dioxide is (12 grams + 2 * 16 grams) = 44 grams per mole.

Using the ideal gas law, we can convert the given volume of 22.4L of carbon dioxide at STP to moles:

(22.4L CO2) * (1 mole / 22.4L) = 1 mole CO2

Since the molar mass of carbon dioxide is 44 grams per mole, the mass of 1 mole of carbon dioxide is 44 grams.

Therefore, the mass of 22.4L of carbon dioxide at STP is 44 grams.

Summary:

In increasing order of their mass in grams, the substances are:

1) 2*10^23 atoms of carbon - 24 grams
2) 2g atoms of oxygen - Not applicable (atoms do not have a mass in grams)
3) 25g of iron - 25 grams
4) 22.4L of carbon dioxide at STP - 44 grams