What number should be placed in the blank to balance the equation 4fe + __O2 = 2Fe2O3

Which of the following substance is not an acid? 1. Substance A is tested and found to have a pH of 3. 2. Substance B, a common food, tastes sour. 3. Substance C causes metals to corrode. 4. Substance D feels slippery in solution.

Every atom has atleast two shells?

Which type of mixture can be separated using a sieve? A: a homogeneous mixture with components of varying sizes B: a homogeneous mixture with components of the same size C: a heterogeneous mixture with components of the same size D: a heterogeneous

which functional group is more electronegative, amine C-NH, or alcohol C-OH, in assigning carbon environment?

A man weighs 162 lbs. What is his mass in mg? (453.6 g = 1 pound)

Which of following statements is true about scientific knowledge? Scientific ideas are not subject to change, so scientific knowledge stays the same. Scientific knowledge is constantly evolving as new observations are made.

Why is ice cream a mixture

Which of the following is a type of cell organelle? A. membrane B. cytoplasm C. DNA D. nucleaus

Electromagnetic forces are the predominant force in holding what subatomic particles together?

When in a compound, the oxidation number of a nonmetal: A). is always fixed and can never be changed B). can only be deduced once all the other oxidation numbers in the equation are totaled C).