Fron(II) chloride is a product of the reaction between iron metal and hydrochloric acid as shown in the equation: Fe + 2HCI → FeCl2 + Hz. What is the change in oxidation number for iron in this reaction?
A From 0 to 2
B. From 1 to 2
c. From 0 to 2
D. From 1 to 2

Which of the following statements is not true? • a. covalent compounds have low melting and boiling points. • ob. covalent bonds between atoms of a compound are relatively weak compared to bonds between molecules. • c. covalent bonds occur between nonmetals. • d. covalent compounds are often gases or liquids.

Astudent carefully transfers 30 g of water and 30 g of alcohol in a glass tube, forming two layers and filling the tube completely. after sealing the tube, the student mixes the solutions, and notices a bubble that forms in the tube. what is the mass of the contents in the glass tube after mixing?

Which of the following describes a compound? (hint: carbon and oxygen bo a. a piece of pure carbon, containing only carbon atoms b. oxygen gas surrounding a solid piece of carbon c. a substance made of two oxygen atoms for each carbon atom carbon and oxygen atoms mixed without being bonded together