What is a controlled experiment?

A. one variable is changed at a time

B. none of the variables are changed

C. all variables are kept constant

D. two variables are changed at a time

The reaction between nitrogen and oxygen is given below: 2 N2 (g) + O2 (g) 2 N2O (g) We therefore know that which of the following reactions can also occur?

Element that has two isotopes has an average atomic mass of 199.7. if 75.56% of the atoms of the element have an atomic mass of 197.4, what is the atomic mass of the other isotope?

Why must sample spots be above the solvent in paper chromatography

Predict what will be observed in each experiment below. A student sees tiny bubbles clinging to the inside of an unopened plastic bottle full of carbonated soft drink. The student squeezes the bottle. A. The bubbles will shrink, and some may vanish.

Why were foreigners allowed to hold office for the Mongols

What is the word equation for KNO3 = KNO2 + O2

Which of the following is true of mixtures? A) a mixture is a combination of two or more substances in which each substance retains its own properties B) A mixture is composed of a single pure substance C) A mixture must contain multiple compounds

Identify the main source of energy used by most organisms

Write a net ionic equation to show that codeine, c18h21o3n, behaves as a bronsted-lowry base in water.

What is the name of the hybrid orbitals used by chlorine in clf3?