In the equation PbO2 + 4HCl → 2H2O + PbCl2 + Cl2, how many electrons are transferred? A. 1 B. 2 C. 3 D. 4

How many atoms are in 5 grams of Fe2O3? (ITS NOT 5)

An ion of oxygen contains eight protons and has a charge of 2-. What must occur for this ion to become a neutral oxygen atom? Group of answer choices It must lose two electrons. It must gain two protons. It must gain two electrons.

What is the density (g/ml) of a sample of mineral oil. if 250ml has a mass of 0.23kg

Which term represents the fixed proportion of elements in a compound.

During a science lab investigating chemical reactions, Mr Grace students place an antacid tablet in a ziplock bag. They recorded the mass of the tablet, 25 g, in the bag, 60 grams. Then they carefully added 50 g of water and quickly seal the bag.

Which material best absorbs sound waves in a room? a. heavy curtains b. hardwood floors c. brick walls d. cement floors

Does density of water depend on the amount of water present?

Which of the following air fronts does not move? a Occluded front b Cold front c Stationary front d Warm front

Kwame wants to measure the volume of water contained in a disposable foam coffe. Which should he use? Nanoliters? Milliliters? Or liters?

Which of the following changes the solid Earth the most?