A piece of copper had mass 3.4 grams before a reaction and 1.79 grams after the reaction. How many moles of copper reacted? (HINT: 3.4g Cu – 1.79 g Cu = 1.61 g Cu used)

Ineed ! it’s science and it’s due tomorrow!

Which real-world scenarios below represent physical and chemical changes? -running a car -exploding fireworks -mixing water and powdered drink mix -combining oil and vinegar to make salad dressing -taking aspirin for a headache -diluting bleach with water-digesting dinner-spreading peanut butter on bread

Identify one disadvantage to each of the following models of electron configuration: -dot structures -arrow and line diagrams -written electron configurations type in your answer below. (answer) -dot structures do not show the distribution of electrons in orbitals and take up a lot of space. -arrow and line diagrams take up a lot of space and make it difficult to count electrons. -written configurations make it easy to lose count of electrons and do not show the distribution of electrons in orbitals.