Take a look at this sketch, and then answer the questions below about the mass, volume and density of Objects D and C. Which object has the greater mass? Which object has the greater volume? Which object has the greater density? о neither (they are the same) unknown (can't be decided with this sketch) о ° о о

Is the density of a gaseous substance larger or smaller than the density of a liquid or a solid at the same temperature? Why?

On the planet Xgnu, the most common units of length are the blim (for long distances) and the kryll (for shorter distances). Because the Xgnuese have 14 fingers, perhaps it is not surprising that 1400 kryll = 1 blim. Two cities on Xgnu are 36.2 bum apart. What is this distance in kryll? The average Xgnuese is 170 kryll tall. What is this height in bums? This hook is presently being used at Xgnu University. The area of the cover of this book is 72.5 square krylls. What is its area in square bums?

Although your textbook lists (he rules for converting an ordinary number to scientific notation, oftentimes students remember such rules better ¡f they put them into their own words. Pretend you are helping your 12-year-old niece with her math homework, and write a paragraph explaining to her how to convert the ordinary number 2421 to scientific notation.

In e-ach of the following pairs, which has the greater mass? (See Table 1.5.) a. 1.0 kg of feathers or 1.0 kg of lead b. 1.0 mL of mercury or 1.0 mL of water c. 19.3 mL of water or 1.00 mL of gold d. 75 mL of copper or 1.0 L of benzene

Which of the following are elements, and which are compounds? a NaOH; b BaCl2; c He; d Ag; e Fe2O3.

Consider the sample of matter in the illustration below. Answer each question independently and explain your answers. a Is the sample homogenous or heterogeneous? b Is the sample a pure substance or a mixture? c Are the particles elements or compounds? d Is the sample a gas, a liquid, or a solid?

1.14 Which part of the following descriptions of a compound or element refers to its physical properties and which to its chemical properties? (a) Calcium carbonate is a white solid with a density of 2.71 g/cm. It reacts readily with an acid to produce gaseous carbon dioxide. (b) Gray powdered zinc metal reacts with purple iodine to give a white compound.

When elemental iron corrodes it combines with oxygen in the air to ultimately form red brown iron(III) oxide which we call rust. (a) If a shiny iron nail with an initial mass of 23.2 g is weighed after being coated in a layer of rust, would you expect the mass to have increased, decreased, or remained the same? Explain. (b) If the mass of the iron nail increases to 24.1 g, what mass of oxygen combined with the iron?

Scientific models do not describe reality. They are simplifications aid therefore incorrect at some level. So why are models useful?