A teacher dropped one light ball and one heavy ball simultaneously from the roof of a school building. Both balls struck the ground at the same time. The students correctly concluded from this experiment that falling objects

What chemical reactions are responsible for damage to old stone buildings

An atom has 5 protons and 7 neutrons. What is its mass number of amu?

In his science class, Mr. Brown heats a small amount of iodine in a test tube. The iodine changes into a pink gas without changing into liquid. What is this process called A) condensation B) deposition C) evaporation D) melting E) sublimation

One isotope of carbon (C) has exactly the same mass number and atomic mass since it was used as the definition of the atomic mass unit (amu). Which isotope is it and what is its atomic mass?

One million atoms of a particular element have a mass of 1.99 x 10 ^-17 grams. - How many moles of this element are there? - What is the molar mass of this element? - What is the identity of this element?

For the reaction 2Fe + 3Cl2 → 2FeCl3 which of the following options gives the correct reactant:reactant ratio? Fe:Cl2 = 1:1 Fe:Cl2 = 2:3 Fe:Cl2 = 3:2 Fe:FeCl3 = 1:1

A 2.575 g piece of gold (specific heat = 0.129 J/g°C) at a temperature of 75°C is placed into cold water at 10°C. If the gold loses 10.0 J of energy, what is its final temperature in the water? Enter your answer to the nearest whole number of °C.

The complete combustion of gaseous sucrose at a constant pressure absorbs 544 kj of heapt per mole of surcrose. write the balance thermochemical equation for the reaction

Find the acceleration if a car goes from 40 to 50 mph in 5 seconds

What is the percent by mass of nahco3 in a solution containing 10 g of nahco3 dissolved in 400 ml of h2o?