Problem 4
Name two elements that have properties similar to those of beryllium, Be, and have average atomic masses higher than 130.
Problem 4
What is the difference between \(\mathrm{NaOH}(s)\) and \(\mathrm{NaOH}(a q) ?\)
Problem 4
Suppose you use sugar, butter, eggs, and l our to make some cookie dough. You bake the dough in the oven until the cookies are done. Do the ingredients undergo a chemical change? Give evidence to support your answer.
Problem 4
Explain how the copper-cycle experiment supports the claim that copper is an element—a basic building block of matter.
Problem 5
You see a ring with a stone that looks like a diamond but wonder why it’s so cheap. The jeweler says the stone is a type of diamond called cubic zirconia. How can chemical symbols show that cubic zirconia is not a diamond?
Problem 5
Which of these elements are solids at room temperature? a. fluorine, F \(\quad\) b. titanium, Ti \(\quad\) c. lead, Pb d. oxygen, O e. potassium, \(\mathrm{K} \quad\) f. silicon, \(\mathrm{Si}\)
Problem 5
Suppose you have equal amounts of calcium, Ca, in two beakers. In one beaker, you react the calcium with oxygen, O. In the other beaker, you react the calcium with sulfur, S. h e reaction with oxygen forms the compound calcium oxide, CaO. a. What do you predict is the chemical formula of the compound formed from the reaction between calcium and sulfur? b. Which compound has more mass, the compound containing calcium and oxygen, or the compound containing calcium and sulfur? Explain your thinking.
Problem 5
Baking soda is a white powder used for baking or cleaning. When you mix baking soda, NaHCO \(_{3}\) , with vinegar, \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}\) , you get a clear colorless liquid and bubbles of \(\mathrm{CO}_{2}\) . a. Specify the phase of each of the compounds. b. Is this a chemical change? Give evidence. c. Where is the sodium, Na, before the change? At er the change?
Problem 6
You find two containers on a chemical shelf, one labeled \(\mathrm{Cu}_{2} \mathrm{O}(s)\) and a second labeled \(\mathrm{CuO}(s) .\) Are these substances the same or different? Explain.
Problem 6
Which of these elements are nonmetals? a. bromine, Br \(\quad\) b. carbon, \(C \qquad\) c. boron, \(B\) d. thallium, TI \(\quad\) e. phosphorus, P \(\quad\) f. aluminum, Al
