What must models and theories do in order to remain valid? Provide 2 facts.

From the following enthalpy of reaction data and data in Appendix C, calculate ΔH∘f for CaC2 (s) : CaC2 (s) + 2H2O (l) →Ca (OH) 2 (s) + C2H2 (g) ΔH∘=-127.2kJ

Which of the following statements is true? A. To be classified as living, an organism must be made of two or more cells. B. During mitosis, a parent cells splits into two identical daughter cells. C.

A water sample is found to contain 59 ppm zinc. If you drank 972 mL of this water, how many g of zinc would you ingest? Answer in units of g.

4. a) The enthalpy change of combustion of hexane was measured using a calorimeter containing 200 cm3 of water; 0.5g of hexane (C6H14) was burnt. The temperature of the water increased by 30 K. Calculate the enthalpy change of combustion of hexane.

Write about electronic configurations

Which is a non renewable resource that is used to generate electrical energy

How many grams of sulfur (S8S8) must be dissolved in 100.0 g naphthalene (C10H8C10H8) to make a 0.11 mm solution

Mason compare the properties of two compounds magnesium oxide is an ionic compound and hydrogen peroxide is not an ionic compound there for both compounds most likely

Cisplatin is synthesized as follows: K2PtCl4 (aq) + 2NH3 (aq)  Pt (NH3) 2Cl2 (s) + 2KCl (aq) What mass of cisplatin can be made from 100. g of K2PtCl4 and sufficient NH3? What mass of KCl is also produced?

What is the total number of protons in the nucleus of an atom of potassium-42? (1) 15 (3) 39 (2) 19 (4) 42