Which of the following equations is balanced?

2H2 + O2 → 4H2O

4Na + O2 → 2Na2O

Fe2O3 + H2 → 2Fe + 3H2O

CH4 + O2 → CO2 + H2O

The second-order decomposition of NO2 has a rate constant of 0.255 M-1s-1. How much NO2 decomposes in 4.00 s if the initial concentration of NO2 (1.00 L volume) is 1.33 M?

25 How many pairs of electrons are shared between two adjacent carbon atoms in a saturated hydrocarbon? (1) 1 (3) 3 (2) 2 (4) 4

Adding food color to water causes a color change. is this evidence of a chemical reaction? explain

alicia cashed her paycheck and used half her earnings to take 3 friends to dinner. She spent $42.15 on dinner and she brought home more than $20.00. write a inequality to represent the situation, using x to represent the amount of alicia check.

Based on the diagram below, rank the three objects from least dense to most dense. Beaker and objects A. Object X, object Z, object Y. B. Object Z, object Y, object X. C. Object X, object Y, object Z.

A sample of bismuth weighing 0.687 g was converted to bismuth chloride by reacting it first with HNO3, and then with HCI, followed by careful evaporation to dryness. The mass of the bismuth chloride obtained was 1.032 g.

When 1 g of sodium chloride (NaCl) is placed in 100 g of water, a solution results. Once the solution is prepared, water is now considered what part of the solution?

1. How is pressure affected as depth increases? 2. As the sun heats the surface of the oceans, two layers of water result. What separates the layers? 3. How is temperature affected when? (a) the depth increases (b) the latitude increases 4.

Are nails in a jar with water a chemical change

What is the molarity of a solution composed of 4.73 g of potassium iodide (KI) dissolved in enough water to make 0.169 L of solution? Answer in units of M.