9) How do you know a chemical change has occurred?

a. New bonds have formed or bonds have broken.

b. The matter has had a change in state.

c. The temperature has changed.

d. All of the above

e. Only a and c are indicators of a chemical change.

If you had a sample of natural carbon containing exactly 10,000 atoms, determine the number of 12c and 13c atoms present.

Suppose that a solution containing 3.50 grams of sodium phosphate (Na3PO4) is mixed with a solution containing 6.40 grams of barium nitrate (Ba (NO3) 2). Calculate the theoretical yield of barium phosphate (Ba3 (PO4) 2) during this reaction.

Name the elements present in a) zinc sulphide b) sodium oxide

Oxygen gas is formed when two oxygen atoms share electrons. Which kind of compound is oxygen gas? A) Mesonic B) Covalent C) ionic D) polyatomic ion

4.5 * 1025 atoms of nickel equal how many moles? A. 27 mol B. 2.7 * 1048 mol C. 0.75 mol D. 75 mol

How many moles of CO will be produced, if 32.5grams of H2O are produced? C6H6S+6O2=>6CO+3H2O+SO3

Identify and briefly describe two ecosystems in your community that are beyond schoolyard

Is N2H2 a ionic compound?

What do Lewis dot structures show?

300 grams of a compound which contains only carbon, hydrogen and oxygen is analyzed and found to contain the exact same percentage of carbon as it has oxygen. The percentage of hydrogen is known to be 5.98823%.