1.1 - Matter & Chemical Change

Which equation represents condensation?

• A. $\hspace{1em}$ $\ce{Br_2(l)\rightarrow Br_2(g)}$

• B. $\hspace{1em}$ $\ce{H2O\ \left(g\right)\rightarrow\ H2O\ (l)}$

• C. $\hspace{1em}$ $\ce{CO2(s)\rightarrow CO_2(g)}$

• D. $\hspace{1em}$ $\ce{ NaOH\left(aq\right) +\ HCl\ \left(aq\right)\rightarrow\ NaCl\left(aq\right) +\ H_2O(l)}$

Which of the following is an example of a mixture?

• A.$\hspace{1em}$ Sucrose

• B.$\hspace{1em}$ Distilled water

• C.$\hspace{1em}$ Seawater

• D.$\hspace{1em}$ Sodium chloride

Which of the following statements is not a feature of Dalton's Atomic Theory?

• A.$\hspace{1em}$ Elements are made up of very small particles known as atoms.

• B.$\hspace{1em}$ All the atoms of an element are identical in mass but not in size.

• C.$\hspace{1em}$ Compounds are composed of atoms of more than one element.

• D.$\hspace{1em}$ During a chemical reaction, atoms are only rearranged, not created or destroyed.

Which of the following is a characteristic of liquids?

• A.$\hspace{1em}$ Their particles vibrate about fixed positions

• B.$\hspace{1em}$ They can be compressed easily

• C.$\hspace{1em}$ They take up the shape of the container they are in

• D.$\hspace{1em}$ The particles move freely and quickly in all directions

What name is given to a compound composed of two non-metals?

• A.$\hspace{1em}$ Polyatomic ionic

• B.$\hspace{1em}$ Ionic

• C.$\hspace{1em}$ Binary molecular

• D.$\hspace{1em}$ Alloy

Which of the following methods is used to separate a solid from a liquid in a heterogeneous mixture?

• A.$\hspace{1em}$ Distillation

• B.$\hspace{1em}$ Filtration

• C.$\hspace{1em}$ Crystallisation

• D.$\hspace{1em}$ Sublimation

A liquid has a boiling point of $-185 ^\circ\mathrm{C}$. What is this temperature in Kelvin?

• A.$\hspace{1em}$ 88 K

• B.$\hspace{1em}$ $-88$ K

• C.$\hspace{1em}$ 458 K

• D.$\hspace{1em}$ $-458$ K

Which of the following polyatomic ions formulas is incorrect?

• A.$\hspace{1em}$ $\ce{NO^-_3}$

• B.$\hspace{1em}$ $\ce{OH^-}$

• C.$\hspace{1em}$ $\ce{SO^{2-}_4}$

• D.$\hspace{1em}$ $\ce{CO^{2-}_4}$

Which of the following is incorrect?

[Maximum mark: 4]

Ammonium perchlorate is an ionic compound ($\ce{NH4ClO4}$) that reacts with aluminium to make aluminium oxide
($\ce{Al_2O_3}$), aluminium chloride ($\ce{AlCl_3}$), nitrogen monoxide gas ($\ce{NO}$), and water at room temperature.

1. State the balanced chemical equation, including state symbols. [2]
   

2. Outline why a chemical equation must be balanced. [1]
   

3. Outline what you would expect to observe about the mass of the products compared to the mass of the reactants in this reaction. [1]
   

When a solution of lead (II) nitrate is mixed with a solution of potassium hydroxide, a precipitate containing lead (II) ions forms.

Which ions are considered to be the spectator ions?

• A. $\hspace{1em}$ Pb$^{2+}$, NO$_3^-$

• B. $\hspace{1em}$ K$^+$, OH$^-$

• C. $\hspace{1em}$ Pb$^{2+}$, OH$^-$

• D. $\hspace{1em}$ K$^+$, NO$_3^-$

What is the sum of the coefficients when the equation is balanced with whole numbers?

$\ce{\underline{\hspace{1em}}\,C_3H_7OH(l) + \underline{\hspace{1em}}\,O_2(g) -> \underline{\hspace{1em}}\,CO_2(g) + \underline{\hspace{1em}}\,H_2O(l)}$

• A.$\hspace{1em}$ $12$

• B.$\hspace{1em}$ $13$

• C.$\hspace{1em}$ $24$

• D.$\hspace{1em}$ $25$

[Maximum mark: 15]

A solution of an unknown hydrate of calcium chlorate (Ca(ClO$_3$)$_2$ $\cdotp$ n H$_2$O) is made by dissolving 4.164 $g$ in 150.0 cm$^3$ of water. The resulting solution of calcium chlorate has a concentration of 0.1142 $mol \ dm^{-3}$.

1. 1. Determine the number of moles and the mass of calcium chlorate present in the solution. [2]
      

   2. Determine the mass of water and then the number of moles of water that was present in the hydrate used to make the original solution. [2]
      

   3. Determine the value of n in the hydrate formula, Ca(ClO$_3$)$_2$ $\cdotp$ n H$_2$O. [1]
      

2. The calcium chlorate solution made above is then mixed with 200.0 $cm^3$ of $0.07500 \ mol \ dm^{-3}$ sodium phosphate (Na$_3$PO$_4$ ), producing a precipitate of calcium phosphate, Ca$_3$(PO$_4$)$_2$.

   1. Write the net ionic equation for this reaction, including state symbols. [2]
      

   2. Determine the limiting reactant in this reaction, showing your work. [2]
      

   3. If 1.535 $g$ of calcium phosphate is recovered, determine the percent yield in this reaction. [3]
      

   4. Determine the concentration of phosphate ions remaining in the solution after removing the precipitate, assuming that is the only loss of phosphate ions. [3]
      

[Maximum mark: 7]

The diagram below represents the heating of ice starting at $-20 ^\circ \mathrm{C}$.

1. Complete the table. [5]
   

   Segment number	What phase(s) is/are present?	What is happening at the particle level?	What phase change, if any, is taking place?
   1
   2
   3
   4
   5

2. Give the melting point of the substance. [1]
   

3. Identify the state of particles at $110^\circ\mathrm{C}$. [1]
   

[Maximum mark: 6]\

Chemical reactions can be classified into different types.

1. For each of the word equations below, identify the type of chemical reaction taking place. [3]
   

   1. Potassium chlorate decomposes to potassium chloride and oxygen gas.

   2. Zinc reacts with hydrochloric acid to produce zinc chloride and hydrogen gas.

   3. Ammonia combines with hydrogen chloride producing ammonium chloride.

2. In the table below, write the formulas of the products formed when double replacement reactions take place between the given reactants. [3]
   

• 	Reactants	$\quad$Products$\quad$
  (i)	$\ce{AgNO_3}$ and $\ce{KI}$
  (ii)	$\ce{HCl}$ and $\ce{Ba(OH)_2}$
  (iii)$\hspace{1em}$	$\quad\ce{Pb(NO_3)_2}$ and $\ce{K_2SO_4}\quad$

[Maximum mark: 3]

The table below shows the data gathered by a chemist regarding substances A, B, and C. Using the data given, discuss which is a pure substance or a mixture. If the substance is a pure substance, determine whether it is an element or a compound.

Substance	Appearance	Melting point	Observed property
A	White crystalline solid	$801^\circ\mathrm{C}$	In aqueous solution, it reacts with silver nitrate forming a precipitate of silver chloride
B	Silver metallic appearance	$660^\circ\mathrm{C}$	Reacts with oxygen forming an oxide
C	Fine white crystalline solid	$186^\circ\mathrm{C}$ - $800^\circ\mathrm{C}$	Readily dissolves in water

Which of the following would be the products of the double replacement reaction below?

$\ce{Pb(NO_3)_2 + KI -> \,\,\,?}$

• A.$\hspace{1em}$ $\ce{K(NO_3)_2}$ and $\ce{PbI}$

• B.$\hspace{1em}$ $\ce{K_2NO_3}$ and $\ce{PbI_2}$

• C.$\hspace{1em}$ $\ce{PbI}$ and $\ce{KNO_3}$

• D.$\hspace{1em}$ $\ce{KNO_3}$ and $\ce{PbI_2}$

[Maximum mark: 11]

Siderite is a mineral containing iron in the form of iron (II) carbonate, FeCO$_3$.

A 15.00 $g$ sample of impure siderite was ground into a fine powder and dissolved in 250.0 $cm^3$ of hot water, and then filtered to remove the insoluble components. After filtration, a 35.00 $cm^3$ sample of the iron solution was analyzed via redox titration using a 0.120 $mol \ dm^{-3}$ solution of potassium dichromate. The balanced redox equation is given below:

Cr$_2$O$_{7(aq)} ^{2-}$ + 14 H$^+_{(aq)}$ + 6 Fe$^{2+}_{(aq)}$ $\rightarrow$ 2 Cr$^{3+}_{(aq)}$ + 6 Fe$^{3+}_{(aq)}$ + 7 H$_2$O$_{(l)}$

1. 1. Calculate the theoretical percent composition of iron in a sample of pure siderite or iron (II) carbonate. [1]
      

   2. If 18.1 $cm^3$ of dichromate solution is used to titrate the actual iron sample to the equivalence point, calculate the number of moles of iron in the titrated sample. [2]
      

   3. Using your value from (ii), determine the mass of iron present in the original sample of siderite. [2]
      

   4. Using the experimental number of moles of $\ce{Fe^{2+}}$ found in (ii), calculate the experimental mass of iron carbonate (FeCO$_3$) in the impure sample and then calculate the percent of impurities found in this sample. [2]
      

2. Another iron-containing mineral is a hydrate of iron sulfate, Fe$_x$(SO$_4$)$_y$ $\cdotp$ $n H_2$O, pure sample is first heated to drive off all of the water. After heating to a consistent mass, a sample with a mass of 5.250 $g$ is found to have 3.561 $g$ of anhydrous material remaining. The remaining anhydrous material was analyzed and found to have 36.76$\%$ iron, 21.11$\%$ sulfur, and 42.13$\%$ oxygen.

   1. Determine the empirical formula of the anhydrate. [1]
      

   2. If the molar mass of the hydrate is determined to be 151.92 $g \ mol^{-1}$, what is the actual formula of the anhydrate? [1]
      

   3. Use the information given in part b(i) to determine the number of moles of water present and, thus, the formula of the hydrate. [2]