What are the significant figures in 250?

A phase change is an example of a A. nuclear change B. physical change C. chemical change D. covalent change

A grey rock with white and black flecks. Is this rock a pure substance, mechanical, or a solution? Explain

Which characteristic might identify a substance as an Arrhenius base? A) It contains an OH group. B) It contains hydrogen ions. C) It forms halogens. D) It will react with other bases.

A sample of air occupies 2.50 L at a temperature of 22.0c. what volume will this sample will this occupy inside a hot air baloon at a temperature of 43.0c assume that the pressure inside the balloon remains constant.

Which of the following describes a chemical change? a. ethanol boils when heated. b. ethanol has a high heat capacity. c. ethanol can be produced by the fermentation of grapes. d. ethanol is a clear

How many hydrogen atoms are in 2.80 mol of ammonium sulfide?

What is a large oval structure that directs all of the cells activities?

HBr + H₂SO₄ SO₂ + Br₂ + H₂O What is the oxidation number of the oxidizing agent? What is the oxidation number of the reducing agent?

How do find the volume of 60.0g of ether if the density is. 70g/mL?

A population of crabs live on a light-colored sandy beach. In this environment there is a population of birds that eat the crabs. One year, there is a volcanic eruption near the beach and dark volcanic ash covers the beach.