*Unit A Chemistry Benchmark

Which indicates a physical change? a change in state a release of heat formation of a precipitate formation of a new substance Which is the simplest substance? oil salt - NaCl sulfur - S water - H2O There is a bold, staircase line on the periodic table. Which term best describes the elements on this line? gases metals metalloids nonmetals Which best describes sodium chloride (NaCl)? a mixture which is physically produced a mixture which is chemically produced a compound which is physically produced a compound which is chemically produced Which of these elements has the greatest atomic number? tinSn leadPb boronB sulfurS Which element most likely has similar physical properties to potassium (K)? arsenic (As) bromine (Br) krypton (Kr) sodium (Na) Which two elements are most likely ductile? C and P Zn and N Si and Ne Ag and Au After a scientist mixes two clear solutions, he is unable to detect a temperature change. However, he knows a chemical change occurred. Which evidence best proves a chemical change did indeed occur? There was an increase in the mass of the new solution produced. A solid precipitate was produced which settled out of the solution. There was a decrease in the volume of the new solution produced. Two distinct layers were observed when the two original solutions were combined. Which describes a chemical change taking place? Water boils when heat is added. Water vapor surrounds melting ice cubes. Color changes when food coloring is added to water. Gas bubbles form when a substance is put into water. Burning a piece of wood releases gases, soot and water vapor into the air. Which best describes this example? A physical change is occuring. A chemical change is occuring. A precipitate forms as the wood burns. Temperature decreases when wood burns. Which is classified as a mixture? neptunium - Np oxygen - O propane - C3H8 saltwater Which best explains the reaction shown below?CH4+ 2O2---> CO2+ 2H2O a physical change, because the reaction produced the same substances a chemical change, because the reaction produced two different substances a chemical change, because the products and the reactant are the same substances a physical change, because the products and reactants are two different substances. Which substance is most likely to react with water in a similar way as sodium (Na)? magnesium (Mg), because it is beside sodium on the periodic table argon (Ar), because it is in the same period as sodium on the periodic table lithium (Li), because it is in the same group as sodium on the periodic table hydrogen (H),because it is in the same group as sodium on the periodic table Which represents a compound? carbon monoxide(CO) aluminum (Al) cobalt (Co) iron (Fe) Which most likely indicates a gas is formed during a chemical reaction? bubbling color change increase in mass formation of a precipitate When heated, copper metal will become a liquid at 1,084 degrees Celsius. Which property of the metal has been described? density reactivity specific heat melting point Which are the most chemically reactive? Group 1 (IA) elements Group 2 (IIA) elements Group 3 (IIIA) elements Group 18 (VIIIA) elements In the formula for table salt, NaCl, what is ratio of sodium to chlorine? It is a one to one ratio. It is a one to two ratio. It is two to one ratio. It is two to three ratio. Properties of four elements were determined and the location of each element of the PTE was identified as shown in the chart below. Which is most likely the element chlorine (Cl)?Element Chemically Reactive Conducts Electricity Location on PTEW yes yes left sideX no no right sideY yes no right sideZ yes no left side element W element X element Y element Z