25%of a first order reaction is completed in 30 mint. Find the time required for completion of 50% of reaction

A 0.907 mole sample of ideal gas at 12C occupies a volume of 4.25L. What is the pressure of gas?

Be sure to answer all parts. Plutonium-242 decays to uranium-238 by emission of an α particle with an energy of 4.853 MeV. The 238U that forms is unstable and emits a γ ray (λ = 0.02757 nm). (a) Write a balanced net equation for these reactions.

Without doing any calculations, determine which mass is closest to the atomic mass of carbon. without doing any calculations, determine which mass is closest to the atomic mass of carbon. 12.00 amu 12.50 amu 13.00 amu

A student calculates the mass of a piece of copper to be 8.3 grams. The actual mass of the copper is 10. grams. What is the percent error? Show your work below. Round your answer to two digits

Which of the following is not a form of radiation? Radio waves or sound waves or microwaves or gamma waves

Change of state may occur when?

During the combustion of 2.00 g of coal, the temperature of 500 g of water inside the calorimeter increased from 25.0°c to 43.7°c. the specific heat of water is 4.18 j/g·°c. how much heat did the reaction generate?

Catalysts are substances that increase the rate of reaction but can be recovered unchanged at the end of the reaction. Catalysts can be classified as either homogeneous (same state as reactants) or heterogeneous (different state than reactants).

How many molecules are there in 79g of Fe2O3?

Which of the following elements is an alkall metal?