Practice Questions

<p>Examine the difference between a molecule of an element and a molecule of a compound. Give one example of each.</p>

<p>Describe the difference between a cation and an anion.</p>

<p>Define &#39;formula unit mass&#39;.</p>

<p>Compare and contrast the terms &#39;atomic mass&#39; and &#39;molecular mass&#39;.</p>

<p>Demonstrate how Dalton&#39;s atomic theory explains the law of definite proportions. Use the example of water ($H_2O$) to illustrate your explanation.</p>

<p>Name the scientist who proposed the law of constant proportions.</p>

<p>Identify the symbols for the following elements: sodium, potassium, and iron.</p>

<p>What is the atomic mass unit (amu) defined as?</p>

<p>Apply the concept of atomic mass to calculate the molecular mass of methane ($CH_4$), given the atomic mass of carbon is 12 u and hydrogen is 1 u.</p>

<p>Describe the law of conservation of mass.</p>

<p>Define a &#39;molecule&#39;.</p>

<p>Examine the role of IUPAC in naming chemical elements and compounds.</p>

<p>Define the term &#39;atomicity&#39;.</p>

<p>Analyze why atoms of noble gases, such as helium (He) and argon (Ar), are generally non-reactive.</p>

<p>Recall the ratio by mass of hydrogen to oxygen in water ($H_2O$).</p>

<p>A compound contains 5.6 g of iron and 3.2 g of sulfur. Analyze the empirical formula of the compound.</p>

<p>Contrast cation and anion with respect to their charge and how they are formed.</p>

<p>List the postulates of Dalton&#39;s atomic theory.</p>

<p>What is the formula mass of sodium chloride ($NaCl$)? (Atomic mass of Na = 23 u, Cl = 35.5 u)</p>

<p>Apply your knowledge of valencies to predict the chemical formula of the compound formed between calcium ($Ca^{2+}$) and phosphate ($PO_4^{3-}$).</p>

<p>Demonstrate how to determine the number of atoms present in one molecule of ammonium sulfate, $(NH_4)_2SO_4$.</p>

<p>Calculate the molecular mass of methane ($CH_4$). (Atomic mass of C = 12 u, H = 1 u)</p>

<p>Apply the law of conservation of mass to analyze the following reaction: $CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O$. If 16 g of $CH_4$ reacts with 64 g of $O_2$, what is the expected mass of $CO_2$ and $H_2O$ produced?</p>

<p>Analyze the composition of magnesium oxide (MgO). If 24 g of magnesium combines completely with 16 g of oxygen, calculate the simplest whole number ratio of magnesium to oxygen atoms in the compound.</p>

<p>Solve for the chemical formula of a compound formed between aluminum ($Al^{3+}$) and oxygen ($O^{2-}$).</p>

<p>Explain how Dalton&#39;s atomic theory explains the law of definite proportions.</p>

<p>List the rules to follow while writing a chemical formula.</p>

<p>Calculate the formula unit mass of sodium carbonate ($Na_2CO_3$), given the atomic masses of Na = 23 u, C = 12 u, and O = 16 u.</p>

<p>If 4 g of hydrogen reacts with 32 g of oxygen to form water, and you have 12 g of hydrogen and 80 g of oxygen, calculate how much water can be formed. Which reactant is limiting?</p>