1.If the temperature is 20. °C, what is the corresponding temperature on the Fahrenheit scale? #2.In the early studies of chemistry, scientists used properties and changes to help identify compounds. This is still done today. If you were given the following observation about a solid, how would you classify it? "This solid is shiny." is this a  physical property chemical property physical change chemical change

A Part A Planet X rotates in the same manner as the earth, around an axis through its north and south poles, and is perfectly spherical. An astronaut who weighs 943.0 N on the earth weighs 910.0 N at the north pole of Planet X and only 850.0 N at its equator. The distance from the north pole to the equator is 18,850 km, measured along the surface of Planet X. How long is the day on Planet X? Express your answer in hours. ΜΕ ΑΣΦ t = Submit Request Answer Part B ? h If a 45,000 kg satellite is placed in a circular orbit 4000 km above the surface of Planet X, what will be its orbital period? Express your answer in seconds. VAZO ΜΕ ΑΣΦ ? T = Submit Request Answer S

1. In the olden days, US minted pennies were pure copper, but copper got so expensive that a pure copper penny was worth more than I cent. Modern pennies are composed of zinc and coated with copper. A student determines the mass of a penny to be 2.482 g. After making several scratches in a penny, the student puts the penny into hydrochloric acid, where the zinc (but not the copper) reacts with hydrochloric acid via a single replacement reaction. The hydrogen is collected at 25°C over water. The collected gas occupies 0.899 L at a total pressure of 791 mm Hg. A. Calculate the moles of hydrogen produced in the reaction. (Hint: Use the Table 1. to determine the vapor pressure of water and assume that all of the zinc in the penny dissolves.) B. Write a balanced chemical reaction for zinc and hydrochloric acid. C. Use stoichiometry to calculate the mass of zinc in the penny. D. Determine the percent zinc (by mass) in the penny.

a white powder is cooled from the crucible