Calculate the molality of a solution formed by adding 4.40 g nh4cl to 11.0 g of water.

[NaCl] = 6.84 m

Explanation:

Molality is mol of solute / 1 kg of solvent

Let's convert the mass of solvent to kg

11 g = 0.011 kg

Now, let's convert the mass of solute to moles

Mass / molar mass

4.4 g / 58.45 g/mol = 0.0752 moles

Molality → 0.0752 mol / 0.011 kg = 6.84 m

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.