Exam 2: Atoms, molecules, and Ions

How many of the following postulates of Dalton's atomic theory are still scientifically accepted? I.All atoms of the same element are identical. II.Compounds are combinations of different atoms. III.A chemical reaction changes the way atoms are grouped together. IV.Atoms are indestructible.

The Greeks proposed that matter consisted of four fundamental substances:

Which of the following is incorrectly named?

Write the formula for: -cobalt(II)chloride

Which of the following pairs is incorrect?

The chemist credited for inventing a set of symbols for writing elements and a system for writing the formulas of compounds (and for discovering selenium,silicon,and thorium)is

Arsenopyrite is a mineral containing As,Fe,and S.Classify each element as metal,nonmetal,or metalloid.

The number of neutrons in an atom is the same for all neutral atoms of that element.

Write the formula for: -iron(III)oxide

Which of the following statements is (are)true?

Which of the following is incorrectly named?

All of the following are characteristics of nonmetals except:

Rutherford's experiment was important because it showed that:

The formula for calcium bisulfate is

The scientist who discovered the law of conservation of mass and is also called the father of modern chemistry is

Write the formula for: -dichlorine heptoxide

Write the formula for: -sulfurous acid

Write the formula for: -nitric acid

Three samples of a solid substance composed of elements A and Z were prepared.The first contained 4.31 g A and 7.70 g Z.The second sample was 35.9% A and 64.1% Z.It was observed that 0.718 g A reacted with Z to form 2.00 g of the third sample.Show that these data illustrate the law of definite composition.

Consider the following two compounds: H₂O and H₂O_{2 .}According to the law of multiple proportions,the ratio of hydrogen atoms per gram of oxygen in H₂O to hydrogen atoms per gram of oxygen in H₂O₂ is