How are scientific questions answered?

O

A. By predicting a solution to the question

O

B. By observing and measuring the physical world

O

C. By reading books about the question

O

D. By asking other scientists what they think

What is a non example of nucleic acids?

What is the effect on the concentration of hydrofluoric acid, hydronium ion, and fluoride ion when the following are added to separate solutions of hydrofluoric acid? (a) HCl (b) KF (c) NaCl (d) KOH (e) HF

A student has two substances at a lab table. One substance is iron pyrite (fool's gold) and the other is real gold. After placing a 20.0-gram sample of iron pyrite into 40.0 mL of water in a graduated cylinder, it displaces 4.0 mL of water.

A bus can travel 63 miles in 1.4 hours. If its speed is increased by 10 mph, how far can the bus travel in 4 hours? miles

Write a balanced chemical equation for the standard formation reaction of gaseous hydrogen fluoride hf

Calculate the percent yield when 500 grams of carbon dioxide react with an excess of water to produce 640 grams of carbonic acid. CO2 + H2O - --> H2CO3

Which of the following is a possible equivalence that can be used in a conversion? A. ten to the negative second power hL over one L B. ten to the negative second power cL over one L C. ten to the first power L over one daL D.

Which process is a chemical change? burning a match boiling water melting ice breaking glass

What form of matter is "vapor"? a. a solid made of a substance that is usually liquid c. a gas made of a substance that is usually solid b. a liquid made of a substance that is usually gas d. a gas made of a substance that is usually liquid

Which of the following atoms releases more energy than oxygen when an electron is added to its valence energy level? Select one: a. helium (He) b. fluorine (F) c. carbon (C) d. nitrogen (N)