Chemistry Random Retrieval Y12

The members of the homologous series of alkanes:

(i) are all straight-chain compounds

(ii) have the general formula C_nH_(2n + 2)

(iii) have identical chemical properties

(iv) show a regular gradation of physical properties as the number of carbon atoms increases.

The carbonates of group 2 metals (M):

(i) have the formula of the form MCO₃

(ii) are insoluble in water

(iii) become more difficult to decompose on heating down the group

(iv) decompose on heating to the metal and carbon dioxide

Which of these properties of magnesium are also properties of beryllium?

(i) It forms a basic oxide

(ii) It forms an ionic chloride

(iii) It reacts with dilute hydrochloric acid

(iv) It forms a stable oxide with the formula MO (where M represents the metal atom)

An example of an endothermic change is the:

For which of the following equations is the value for standard enthalpy change equal to the standard enthalpy of formation of sodium chloride?

What is the electronic configuration of scandium? Enter your answer in the following format 1s2 2s2 etc. (note the space between each sub-shell!) Follow the aufbau order of sub-shell filling.

Sodium hydride reacts with water:

NaH_(s) + H₂O_(l) -> NaOH_(aq) + H_2(g)

What is the concentration of a solution of sodium hydroxide formed when 0.600 g sodium hydride reacts with water and the solution is diluted to 100 cm³?

Which of these compounds consist of molecules which are linear?

(i) water

(ii) beryllium chloride

(iii) sulfur dioxide

(iv) carbon dioxide

The ionic equation for a neutralisation reaction is:

Which of these reactions is an acid-base reaction?

Which of these compounds has a relatively low melting point (below 500 ^oC)?

Which of these true statements can help to explain why magnesium has a higher melting point than sodium:

(i) magnesium atoms/ions are smaller than sodium atoms/ions

(ii) the metallic bonds are stronger in magnesium than in sodium

(iii) a magnesium atoms contributes two bonding electrons not one

(iv) the first ionisation energy is higher for magnesium than for sodium.

Steel and graphite are similar in that they both.

(i) conduct electricity

(ii) are dark grey/black when powdered

(iii) can have high tensile strength

(iv) are brittle

What is/are the bond angle(s) found in PCl₅?

(i) 90^o

(ii) 104.5^o

(iii) 120^o

(iv) 180^o

In the formula of water, H-O-H, the lines represent:

(i) shared pairs of electrons

(ii) dative bonds

(iii) covalent bonds

(iv) hydrogen bonds

A chloride ion and an argon atom have the same:

(i) number of protons

(ii) number of electrons

(iii) atomic number

(iv) electron configuration

Which of these sets of properties is that of an ionic compound?

Analysis of a sample of potassium in a mass spectrometer shows that it consists of 93.2% potassium 39 and 6.8% potassium-41. What is the relative atomic mass of potassium?

When iron(II) chloride solution mixes with silver nitrate solution some silver metal precipitates and the mixture reaches an equilibrium state.

Fe²⁺_(aq) + Ag⁺_(aq) <=> Fe³⁺_(aq) + Ag_(s)

When the aqueous layer is decanted off, the precipitate of silver redissolves on adding a solution of:

Using enthalpies of formation Δ_fH, calculate the enthalpy change for the following reaction.

2NaHCO_3(s) => Na₂CO_3(s) + H₂O_(l) + CO_2(g)

Select the data from the 'Selection of Enthalpies of Formation and Combustion' shown above.

If this question was generated from Random Retrieval, this data can also be found in TOOLS>Data Sheets.

A solution of Br₂ and KI were mixed. Then shaken with cyclohexane. Which is correct?

(i) the bromine is reduced

(ii) the cyclohexane layer goes brown

(iii) the cyclohexane layer goes purple

(iv) the iodine is reduced

When chlorine reacts with cold, aqueous sodium hydroxide the ions formed are:

Which of the following increase from left to right along the series Mg - Ca - Sr - Ba?

(i) the thermal stability of the nitrates

(ii) the thermal stability of the carbonates

(iii) the solubility of the hydroxides in water

(iv) the solubility of the sulfates in water

What is the oxidation number of OXYGEN in hydrogen peroxide

H₂O₂

What is the oxidation number of CARBON in methanal

CH₂O

What is the oxidation number of SULFUR in

SO₄^2-

What is the oxidation number of CARBON in

CO₂

An element which is a solid at room temperature consisting of molecules is:

Choose one of the following options:

A compound X with the molecular formula C₄H₁₀O has a broad peak in its IR spectrum at 3500cm^-1.

Oxidation of X with excess potassium dichromate(VI) gives a product Y which is not an acid and does not reduce Fehling's solution.

Y has a strong peak in its IR spectrum at 1700cm^-1.

Identify X and Y. (See also the data in question 9.)

There are two main peaks in the infra-red spectrum of carbon dioxide.

This shows that carbon dioxide molecules:

Species such as CH₃⁺ and Br⁺ can be detected in a mass spectrum but do not occur in chemical reactions under typical laboratory conditions.

This is because in a mass spectrometer:

Which is the correct sequence of events that takes place in a modern mass spectrometer in the production of a mass spectrum from a sample of an element or compound?

Products formed by heating 2-bromo-3-methylbutane with a solution of potassium hydroxide in ethanol (an elimination reaction) include:

(i) 2-methylbut-1-ene

(ii) 3-methylbut-2-ene

(iii) 2-methylbut-3-ene

(iv) 3-methylbut-1-ene

What is the mechanism for the reaction of bromine with prop-1-ene?

What is the H-C-H bond angle in ethene?

At a high temperature in the presence of steam, the alkane C₁₆H₂₄ reacts to form a mixture of ethene, propene and ethane. This is an example of:

How many monosubstitution products can be formed when butane reacts with chlorine?