Which of the following is a chemical change?

a. sulfur and iron filings are mixed together in a beaker at room temperature.

b. sulfur and iron filings are mixed together and the iron is removed with a magnet.

c. a mixture of sulfur and iron filings are heated until the contents glow red and the appearance of the mixture changes. a magnet can no longer remove iron filings.

d. a mixture of sulfur and iron filings are placed in carbon disulfide, the sulfur dissolves, leaving iron behind in the bottom of the beaker.

The image shows a process that releases nuclear energy which statement best identifies the process shown the process must be fusion because energy is released the process must be fusion because of have your nucleus formed a smaller nuclei the process must be fission because a large nucleus breaks into smaller nuclei the process must be fission because neutrons are formed

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н, о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.

What substance has a mass of 9.5g and volume of 2.1cm^3