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A sound is sampled and recorded digitally. The sound is sampled at a rate of 48 000 samples per second (Hz) for 3 minutes using a 16-bit sample resolution. Calculate the size of the digital recording, giving your answer in mebibytes. Give your answer rounded to 2 decimal places. You should show your working. [2 marks] Answer mebibytes 0 1 . 2 The highest frequency component in a different sound is 15 000 Hz. What is the minimum sampling rate that should be used when recording this sound ...

AQA A LEVEL CHEMISTRY PAPER 1,7405/1|PAPER 2,7405/2|PAPER 3,7405/3 VERSION 1.0 FINAL QUESTION PAPERS & MERGED MARKING SCHEME | JUNE 2023|MARKING SCHEME 100% CORRECT

AQA AS CHEMISTRY PAPER 1 .7404/1|PAPER 2,7404/2 VERSION 1.0 FINAL QUESTION PAPERS & MERGED MARKING SCHEME | JUNE 2023

Ethyl ethanoate can be made by reacting ethanol with ethanoic acid in the presence of concentrated sulfuric acid. Method 1. A mixture of ethanol, ethanoic acid, and concentrated sulfuric acid, with anti-bumping granules, is heated under reflux for 10 minutes. 2. The apparatus is rearranged for distillation. 3. The mixture is heated to collect the liquid that distils between 70 and 85 °C 4. The distillate is placed in a separating funnel. Aqueous sodium carbonate is added, and a stopper ...

Shade in one lozenge to indicate which of the following values is an irrational number. [1 mark] A 3 4 B √2 C 73 D –19 0 1 . 2 Shade in one lozenge to indicate which of the following values is a natural number. [1 mark] A 3 4 B √2 C 73 D –19 0 1 . 3 Define the set of real numbers.

Shade in one lozenge to indicate which of the following values is an irrational number. [1 mark] A 3 4 B √2 C 73 D –19 0 1 . 2 Shade in one lozenge to indicate which of the following values is a natural number. [1 mark] A 3 4 B √2 C 73 D –19 0 1 . 3 Define the set of real numbers.

This question is about rates of reaction. Figure 1 shows apparatus used to measure the rate of reaction when an acid reacts with an excess of solid sodium hydrogencarbonate, NaHCO3 When different monoprotic organic acids are used, the rates at which gas escapes can be used to compare the strengths of the acids. A timer is started when the NaHCO3 is added to the acid and the mass of CO2 gas lost is recorded at regular intervals. (It is assumed that any change in mass is due to the loss of ...

This question is about complexes of the transition metal chromium. 0 1 . 1 State the meaning of the term transition metal complex. [1 mark] Cr(PF3)6 is a complex of chromium that contains molecules of PF3 0 1 . 2 The electron pair repulsion theory can be used to predict the shape of a PF3 molecule. Draw the shape of a PF3 molecule. Include any lone pairs of electrons that influence the shape. Name the shape. [2 marks] Shape Name of shape 0 1 . 3 Suggest why the oxidation state of chro...

This question is about the analysis of organic compounds. For each pair of compounds in Questions 01.1 and 01.2, give a reagent (or combination of reagents) that could be added separately to each compound in a single reaction to distinguish between them. State what is observed in each case. 0 1 . 1 CH3CH2CH2CHO and CH3CH2CH(OH)CH3 [3 marks] Reagent(s) Observation with CH3CH2CH2CHO Observation with CH3CH2CH(OH)CH3 0 1 . 2 Cyclohexane and cyclohexene [3 marks] Reagent(s) Observation w...