Which of the following is a sign that a chemical change has taken place when wood burns?

bubbles

rust

production of a liquid

production of heat

What is the purpose of drawing a dohr model of an atom?

One mole of helium atoms has a mass of 4 grams. if a helium atom in a balloon has a kinetic energy of 1.224e-21 j, what is the speed of the helium atom? (the speed is much lower than the speed of light.) v = 6.

When light passes from one medium to another, resulting in a change in speed and direction of insolation,?

2. Tony sets up an experiment inside his classroom. He spaces 5 plants at equal distances along a straight line, with the first plant directly in front of a window and the last plant 10 meters (m) away from the window.

330 grams of boiling water (temperature 100°C, specific heat capacity 4.2 J/K/gram) are poured into an aluminum pan whose mass is 840 grams and initial temperature 29°C (the specific heat capacity of aluminum is 0.9 J/K/gram).

What is the term for the basic unit of electric current? The basic unit of electric current is the.

When a sailboat overtakes a powerboat, which vessel is the stand-on vessel?

Both matter and energy can eneter and exit which of the following systems? A. open only B. both open and closed C. isolated only D. both closed and isolated

1. Find the charge if the number of electrons is 4 x 10-18

Which of the following describes resistance force?