Whats the formula for selenium pentaoxide, iodine trichloride, zinc (1) nitride, chromium (iii) bicarbonate, and there molar mass

answer one of them plz and thx

1) Se2O5

2) I2O6

3)Zn3n2

4) Cr(HCO3)3

Explanation:

selenium pentaoxide (= also called diselenium pentoxide)

= Se2O5

⇒ Se = 78.97 g/mol

⇒ O = 16 g/mol

⇒ 2*78.97 + 5*16 = 237.94 g/mol

iodine trichloride

= I2O6

⇒ I = 126.9 g/mol

⇒ Cl = 35.45 g/mol

⇒ 2* 126.9 + 6 * 35.45 = 466.5 g/mol

zinc (1) nitride does not exist  (it's Zinc(ii)nitride

The oxidation number for zinc is always 2

Zn3n2

⇒ Zn = 65.38 g/mol

⇒ N = 14 g/mol

⇒3*65.38 + 2* 14 = 224.14 g/mol

chromium (III) bicarbonate

Cr(HCO3)3

⇒ Cr = 52 g/mol

⇒ H = 1.01 g/mol

⇒ C = 12 g/mol

⇒ O = 16 g/mol

52 + 3*1.01 + 3*12 + 6*16 = 235.03 g/mol

idk i’m struggling too

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.