Why ethynes are more energy producing through combustion

This lab question is: How can you distinguish a physical change from a chemical change? Which statements below are an appropriate hypothesis in response to this question? Check all that apply.

What is vsepr theory, and how can it be used to predict molecular shapes?

Propane burns according to the following equation: C3H8 (g) + O2 (g) → CO2 (g) + H2O (g) If 465 mL of oxygen at STP is used in the reaction, what volume of CO2, measured at 37.0oC and 98.59 kPa.

The highest parts of a transverse wave are called a. troughs. b. crests. c. nodes. d. wavelengths.

The concentration of reactants or products at any time during the reaction can be calculated from the integrated rate law. True / False.

Which of the following is not a rock? a. granite b. shale c. marble d. diamond

Donna is attempting to make an electromagnet to pick up old nails in and around her driveway. Which of these materials would be best to use for the core in order to make the strongest electromagnet to pick up the most nails?

The amount of silica in the magma and temperature are factors that determine the viscosity of magma.

Valeric acid, an organic acid, contains only C, H, and O. If 0.471 g of the acid burns completely in O2 it gives 1.01 g CO2 and 0.415 g H2O. Determine the empirical formula of the acid.

Ab2 has a molar solubility of 3.72*10-4 m. what is the value of the solubility product constant for ab2? express your answer numerically.