Que cambios son fisicos y cuales son quimicos?

a) quemar papel

b) limpiar objetos de plata

c) hacer hielo en el congelador

d) fundir hierro

What does the subscript 2 show in this chemical equation? h2o → 2h o a. there are 2 oxygen atoms. b. there are 2 hydrogen atoms. c. there is half of a hydrogen atom. d. there are 2 water molecules.

What is the molar mass off a substance?

What happens to the force as you move it away from an object?

Consider the compound CaCl2. What type of compound does it represent? a) organic b) covalent c) ionic d) diatomic

Give the number of significant figures indicated. 0.066 A. 3 B. 0 C. 1 D. 2

Which is the best definition of activation energy? O the energy required to end a chemical reaction O the energy required to bind a substrate to an active site O the energy required to form or break the bonds of reactant molecules O the energy

A chemist wants a 0.100 m solution of naoh. She has 0.0550 mol naoh available. What volume of solution is needed to make the mixture?

Which of the following is the most important factor when determining a safe speed? A) Number of passengers on your boat B) Distance from the nearest safe shoreline C) Presence of a safe water buoy D) Wind, water conditions and currents

Which of the following statements about water is true? It's strongest intermolecular forces are London dispersion forces It's a non-polar molecule It's a solid at room temperature and pressure It's a solid form is less dense than the liquid form

At 25.0 degrees Celsius, one milliliter of mercury has a mass of 13.6g. How many liters of mercury are required to have a mass of 500 Kg of mercury?