Chemistry

19. What is the chemical level of organization?

Determine the number of significant figures in the following measurement: 0.0302 s 2 3 4 5

A 35.0 g piece of aluminum at 405^circ C was placed into a sample of water at 23.0^circ C . The final temperature of the water and aluminum was 55.0^circ C What is the heat change for the aluminum? c_(Al)=0.921(J)/(gcdot ^circ )C q_(Al)=[?]J Round your answer to three significant figures.

MULTIPLE-CHOICE QUESTION What is the atomic number? The number of neutrons in an atom. The number of protons in an atom The number of electrons and neutrons in an atom.

Identify each of the following as a physical or chemical change. 21. __ You leave your bicycle out in the rain and it rusts. 22. __ A sugar cube dissolves. 23. __ Scientist break-up water into oxygen and hydrogen gas. 24. __ Burning coal for a barbecue. 25. __ Trimming a bush because it has grown too tall.

INGREDIENTS One of our 53 Real Ingredients is honey. TRUE FALSE

2. SEP Obtain Information What problem occurs if the firework mixture is not pure (i.e., they are dirty or contaminated)?

How many moles are in 69 grams of oxygen? 3.3 2.3 4.3 17 8 44

What is the term for the relative order of metals arranged by their ability to undergo reaction? activity series reactivity series productivity series elemental series none of the above

Which of the following is evidence for a chemical reaction? change in color change in mass change in physical state all of the above none of the above