What conclusion can you draw when you compare the density of the materials found on Earth's surface (.3000 kg/m3) with the density of Earth as a whole (0.5400 kg/m3) ?

A scientist needs to store 28.0 moles of xenon gas at STP in the lab. What size gas tank will he need? 376 L 473 L 628 1 219 L

Science is based on? A. Facts B. Observations C. Both facts and observations D. Neither facts nor observations

An unknown gas effuses 0.5 times faster than hydrogen gas (H2). What is the molecular mass of the gas? 1.008 g/mol 4.064 g/mol 2.0 g. mol 8 g/mol

4. Which of these metals is a pure element? Brass Bronze Silver Steel 5. C is the correct chemical symbol for ... Calcium Carbon Chlorine Cobalt 6. Which of these substances is an element? Air Fire Oxygen Water

The compound AX2 decomposes according to the equation, 2 AX2 (g) = > 2 AX (g) + X2 (g). In one experiment, AX2 was measured at various times, and these data recorded: Time (s) AX2 mol/L 0 0.0500 2.0 0.0448 6.0 0.0300 8.0 0.0249 10.0 0.0209 20.0 0.

Which term best describes the type of bonding in magnesium chloride

This equation indicates that the reaction gives off heat. What is this type of reaction called? 2C4H10 + ? O2? 8CO2 + 10H2O + heat a. an exothermic reaction b. an endothermic reaction c. absorption reaction d. precipitation reaction

Given the balanced equation representing a reaction: C3H8 (g) + 5O2 (g) = = >3CO2 (g) + 4H2O (g) What is the total number of moles of O2 (g) required for the complete combustion of 1.5 moles of C3H8 (g) ? (1) 0.30 mol (3) 4.5 mol (2) 1.5 mol (4) 7.

What increases in equal steps of one from left to right in the Periodic Table for the elements lithium to neon?

The organisms living together in a community are interdependent upon one another. Look at the food web below. In which of the following ways is a puffin dependent upon salmon? A. Puffins have a commensalistic relationship with salmon. B.