Name: ___________________________________ Date: ______________ Practice Test #3 ____ 1. When a precipitation reaction occurs, the ions that do not form the precipitate A) evaporate B) are cations only C) form a second insoluble compound in the solution D) are left dissolved in the solution E) none of these 2. An aqueous solution of potassium chloride is mixed with an aqueous solution of sodium nitrate. The complete ionic equation contains which of the following species (when balanced in standard form)? A) B) C) D) E) ____ 3.
A) Water is 11% hydrogen and 89% oxygen by mass. B) Water boils at 100°C at 1 atm pressure. C) Water can be separated into other substances by a chemical process. D) Water and salt have different boiling points. E) Water is a compound.
For example, the reaction |BaCl2•2H2O ( BaCl2 + 2H2O |(2) | is reversible, and if water is added to the anhydrous salt BaCl2, formation of BaCl2•2H2O takes place: |BaCl2 + 2H2O ( BaCl2•2H2O |(3) | The reaction of dehydration of hydrated ferrous sulfate |FeSO4•7H2O ( FeSO4 + 7H2O |(4)
25 cm3 of a solution of sodium hydroxide reacts with 15 cm3 of 0.1 mol/dm3 HCl. What is the molar concentration of the sodium hydroxide solution? 4. Succinic acid has the formula (CH2)n(COOH)2 and reacts with dilute sodium hydroxide as follows: (CH2)n(COOH)2 + 2NaOH → (CH2)n(COONa)2 + 2H2O 2.0 g of succinic acid were dissolved in water and the solution made up to 250 cm3. This solution was placed in a burette and 18.4 cm3 was required to neutralise 25 cm3 of 0.1 moldm-3 NaOH.
This gas burns completely in oxygen to form water and 72 cm3 of carbon dioxide only. All measurements are taken at room temperature and pressure. Determine the empirical formula of the binary compound. (1 mole of gas occupies 24 dm3 of volume at r.t.p) A Al2C3 B Al3C4 C Al4C3 D Al5C3 Solution no. of moles of CO2 = 72/(24 000) = 0.003 mol no.
A. II only B. III only C. II and III D. I only 6. A hydrate is a A. buffer solution of water B. compound in which hydrogen is combined with an element less electronegative than itself C. compound containing a definite number of water molecules in its chemical composition D. salt containing the hydroxyl radical 7. Two moles of hydrogen react with 1 mole of oxygen to produce which of the following? A. 1 mole of water B.
Solub. or Reaction w/cold H2O: No reaction Solub. or Reaction w/hot H2O: No reaction Litmus test: No reaction on red or blue. Dilute HCl: Solution turned yellowish, but no actual reaction on copper Dilute NaOH: No reaction Substance: Zn Color: Silver Odor: None Effect of Heat: None Solub. or Reaction w/cold H2O:None Solub.
93 g/mol? Not we get to use it! Yay! 93 g/mol / 31.06 g/mol = 3 (this is the multiplier) Multiply that whole number through the subscripts of the empirical formula. 3 x (C H5 N) = C3H15N3 Hydrated compounds Solving process: 1st- the difference between the initial mass and that of the dry sample is the mass of water that was driven off.
From Hydrogen to DNA Task One – Thinking Questions The movement and mixing of particles is known as diffusion. Explain why diffusion occurs in liquids and gases but not solids. Diffusion occurs in liquids and gases because molecules in a solid don not have the ability to move around. Aluminium has a melting point of 660 degrees Celsius what is its state at a) 1000 degrees Celsius - At 1000 degrees Celsius the state of Aluminium would be a liquid b) 500 degrees Celsius – At 500 degrees Celsius the state of Aluminium would be a solid. How are Neutrons different between Protons?
Kobs is the slope on the graph plotting Vol of NaaS2O3 against time. Specific hydrogen ion catalysis Kobs = KH+[H+] This is used when a strong acid is being used in the reaction as it acid fully dissociated and there is no A- value. This is the equation used for reactions (i), (ii) and (iv) as they used HCl as the acid. General acid catalysis Kobs = KH+[H+] + KHA[HA]. This is used when a weak acid is being used in the reaction as it acid does not fully dissociated and there is an A- value.