Do mixtures have a set composistion

What is a underlying problem affecting the fresh water supply?

Which of the following represents a purely covalent bond? Ne - Ne Na - Na N - N Ni - O

Which of the following is always involved in a scientific inquiry? A. knowing the correct answer before you start B. guessing what would happen instead of doing experiments C. coming up with questions based on observation and reasoning D.

When carbon is burned in air, it reacts with oxygen to form carbon dioxide. When 16.8 gg of carbon were burned in the presence of 60.2 gg of oxygen, 15.4 gg of oxygen remained unreacted. What mass of carbon dioxide was produced?

What is the chemical formula for potassium oxide

Two students design an experiment to see if pushing or pulling a box across the floor is more effective. The first student pushes the box across the floor a distance of 20 feet and the second student times how long it takes.

15.00 g of NH4HS (s) is introduced into a 500. mL flask at 25 °C, the flask is sealed, and the system is allowed to reach equilibrium. What is the partial pressure of ammonia in this flask if Kp = 0.108 at 25 °C for: NH4HS (s) ⇄ NH3 (g) + H2S (g) ?

Among elements 1-18, which element or elements have the smallest effective nuclear charge if we use the equation zeff=z-s to calculate zeff? check all that apply.

Two clear solutions are placed in separate beakers. The first solution has a pH of 4, and the pH of the second solution is unknown. If the two solutions are mixed and the resulting pH is 5, the second solution must have

Based on its location on the periodic table, which element (s) have properties similar to N? Choose all that apply. * P C O Bi