Examine the chemical equation: C17H170N3 (s) + 2C4H603 (1) - ->

C2182105N (s) + 2C2H4O2 (1) Does the equation describe a chemical

change or a physical change? Explain.

A chemist prepares a solution of calcium bromide CaBr2 by measuring out 4.81μmol of calcium bromide into a 50. mL volumetric flask and filling the flask to the mark with water.

When you crush a first-aid pack for an injured athlete and the pack gets cold, which of the following is true? a. A physical change has occurred, with energy being absorbed. b. A chemical change has occurred, with energy being given off. c.

Write the molecular balanced chemical equation and the net ionic equation for the reaction between ca (oh) 2 and hcl

In the laboratory, an unknown element X reacts with fluorine. The following ionic compound is obtained: XF. According to the valence electrons of fluorine, to which family does the element X belong? Select one: a. halogen b. alkali metals c.

In lab you are allowed to eat and drink only: a) if you are very hungry b) if you have washed your hand well c) if the food is healthy and can be digested fast easily. d) None of the above

A penny has a mass of 2.50g and the moon has a mass of 7.35 X 10^22 Use this information to answer the questions below. Be sure your answers have the correct number of significant digits.

If a car tire has a diameter of 3232 inches, what is the approximate circumference of the tire?

9) Bettina spoke into a microphone during the school play to increase the sound of her voice so the audience could hear her speak.

Explain what happens to the average kinetic energy thermal energy and temperature of a substance when the particles in the substance slows down

Which of the following could be used to describe the rate of a reaction? change in time/change in concentration change in mass/change in concentration change in concentration/change in time change in concentration/change in mass