Which is an example of a chemical change?

ripping paper

chopping wood

baking a cake

stretching a rubber band

Consider the nuclear equation below. Superscript 239 subscript 94 upper P u right arrow variable X plus superscript 4 subscript 2 upper H e. What is X?

A 248-g piece of copper is dropped into 390 mL of water at 22.6 °C. The final temperature of the water was measured as 39.9 °C. Calculate the initial temperature of the piece of copper.

Who was the second person to organize the elements on the periodic table and what property did he use to re-organize them?

Calcium has atomic number of 20 how many electrons of a calcium atom are involved in chemical bonding

Jordan wonders why there is dew on the grass in the morning. He asks a few friends to see what they think. His friend Tasha says that there is dew on the grass because it always rains at night. Did Jordan find a scientific answer?

How does water vapor get into the atmosphere?

Which statement a-d about a state function is not correct? A - the value of a stage function can change along a path. B-the final value of a state function is independent of the path taken to reach the final state.

100mL of water initially at 35°C is placed inside a calorimeter. What will be the final temperature in the calorimeter if 50g of aluminum initially at 100°C is added to the water?

Which is an example of a chemical change? ripping paper chopping wood baking a cake stretching a rubber band

Scientists have measured and recorded the average rainfall of an area over several years to see if there is a pattern. Which kind of investigation does this best describe? A. controlled experiment B. systematic observation C. field study D.