A chemist weighed out 49.0 g of calcium. Calculate the number of moles of calcium she weighed out. Be sure your answer has the correct number of significant digits

A gas has a pressure of 2.0 atm. If the temperature decreases from 250K to 125K and the volume remains constant, what will be the resulting pressure?

Write a balanced equation of reaction. Solid potassium chlorate is heated to form solid potassium chloride and oxygen gas. Express your answer as a chemical equation. Identify all of the phases in your answer.

Describe a main goal of primary treatment in a modern sewage treatment plant.

If the net force on a 75-N object is 375 N from the left, in what direction will the object move? Question 2 options: toward the right toward the left in a straight line to the side

If energy cannot be created or destroyed, how is it possible for the products to have more energy?

Ionic compounds are formed by the ... of electrons? by the what?

What is it called when energy is created without oxygen?

If 21.3 grams of lithium react with excess water, how many liters of hydrogen gas can be produced at 297 Kelvin and 1.40 atmospheres? Show all of the work used to solve this problem. 2Li (s) + 2H2O (l) - > 2LiOH (aq) + H2 (g)

How did coroners handle their responsibilities in the early 1900s? Why was there a need for significant change in the job?

Which of the following is the best indication that a chemical change has taken place? a. The matter changes color. b. A mixture separates into layers. c. The change is reversible. d. The shape of the substance changes.