A compound whose empirical formula is NO2 could have a molecular mass of

a. 23

b. 39

c. 92

d. 120

A student placed a stack of rocks on a ramp. She added clumps of soil rooted with live grass. Using a garden hose, she then applied a steady spray of water that soaked into the soil, making it heavier. What does the spray from the hose model? A.

Colligative properties are a. chemical properties. b. physical properties. c. biological properties. d. none of these

Rose reviews the EPA website and finds a recommendation to use cold tap water for cooking instead of starting with warm water from the tap. Why does the EPA site suggest using cold tap water for cooking instead of starting with warm tap water?

What is the percent by mass of a solution that contains 25 g KNO3 in 400.0 g H20?

Compare and contrast plateaus and plains

What part of an atom do we change for isotopes

The Safe Drinking Water Act (SDWA) sets a limit for mercury-a toxin to the central nervous system-at 0.002 mg/L. Water suppliers must periodically test their water to ensure that mercury levels do not exceed 0.002 mg/L.

The smallest unit of an element is a blank

How many sodium atoms will create an ionic bond with sulfur?

Rank the elements from smallest to largest electronegativity negativity (smallest at top) 1. N 2. P 3. As 4. Sb