A teacher wants to perform a classroom demonstration that illustrates both chemical and physical changes. Which would be the best demonstration that she could use to illustrate both the changes?

Describe one technology used to travel to space and one technology used to return from space

Consider the balanced equation below. 4NH3 + 302 → 2N2 + 6H20 What is the mole ratio of NH3 to N2? A) 2:4 B) 4:2 C) 4:4 D) 7:2

Use standard enthalpies of formation to determine ΔHorxn for: 2C2H2 (g) + 5O2 (g) → 4CO2 (g) + 2H2O (l)

What happens in the distillation flask and condenser during distillation.

You are most likely to find a fossil in which of the following? a. grass. b. stone. c. desert sand. d. sedimentary rock.

Where is the energy in a glucose molecule stored

In this reaction: Mg (s) + I₂ (s) → MgI₂ (s) If 2.34 moles of Mg react with 3.56 moles of I₂, and 1.76 moles of MgI₂ form, what is the percent yield?

Using the Acceleration Equation Try it A cyclist going downhill is accelerating at 1.2 m/s2. If the final velocity of the cyclist is 16 m/s is the cyclist's initial velocity? o oo 0 4 m/s O 12 m/s O 18 m/s O 20 m/s

Why is fusion not used to generate electrical power?

Some constellations, such ad Ursa Minor, are visible in the sky year-round; other contellations appear for only part of the year. explain why this happens.