When 25.2 grams of H2 are reacted with an unlimited amount of O2? *
2H2 + O2 → 2 H,0 AHrxn = -241.83 kJ

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Read "who built the pyramids? ”. leave this link open while you answer the questions throughout the assignment. give at least two reasons why some people claim the pyramids of giza were constructed by aliens.

In what way do investigations build scientific knowledge? the results of investigations lead to questions that cannot be tested. they reflect the opinions and social values of scientists, ensuring valid information. the results of investigations lead to new questions, which lead to new investigations. they are not influenced by the research of earlier scientists, so they are able to address gaps in understanding. i