What is a tough, rigid, outer covering that protects some cells and gives them shape?

For the reaction N₂ (g) + 3H₂ (g) ⇌ 2NH₃ (g) what is the value of Kc at 500 ∘C if the equilibrium concentrations are as follows: [H₂] = 0.50 M, [N₂] = 0.50 M, and [NH₃] = 2.1 M? Express the equilibrium constant to two significant figures.

Identify the Brønsted-Lowry acid, the Brønsted-Lowry base, the conjugate acid, and the conjugate base in each reaction: (a) (CH3) 3N (aq) + H2O (l) ⇌ (CH3) 3NH + (aq) + OH - (aq) (b) HNO3 (aq) + H2O (l) ⇌H3O + (aq) + NO3 - (aq) Drag the appropriate

You are given a liquid. Briefly describe the steps you would take to show whether it is a pure substance or a homogeneous mixture.

Which type of radioactive product has zero mass and zero charge?

A sample of 0.53 g of carbon dioxide was obtained by heating 1.31 g of calcium carbonate. what is the percent yield for this reaction? caco3 (s) ⟶ cao (s) + co2 (s)

Which of the following transitions would release energy? n=2->n=3 n=1 - > n=3 n=3 - >n=1 n=3->n=2

Which animal group actually saw a drop in the number of endangered and threatened species between 1995 and 2005? a Fish b. Reptiles c. Birds d. Mammals

Why does burning fossil fuels put ecosystems under pressure?

What is the quantum number set of the ground-state electron that is found in helium (He) but not in hydrogen (H) ? (1, 0, 0, - ½) (1, 0, 1, - ½) (1, 1, 0, - ½) (1, 1, 1, - ½)

What must be true in order for magnetism to induce an electric current in a wire? There needs to be a switch in the circuit. There cannot be a switch in the circuit. The wire must be part of a closed circuit. The wire must be part of an open circuit.