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Problems

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428 problems
Type:
1.
Washing soda is sodium carbonate, Na2CO3. New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by ComputerStemPy LabStemPy Lab
Easy
2.
Phosgene is COCl2, and cobalt chloride is CoCl2. New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by ComputerStemPy LabStemPy Lab
Medium
3.
Ammonium sulphate, (NH4)2SO4, is a fertiliser. New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by ComputerStemPy LabStemPy Lab
Medium
4.
Magnesium burns: 2Mg + O₂ → 2MgO. A jar holds 6.0 g of oxygen, and 6.0 g of magnesium ribbon burns… New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by ComputerStemPy LabStemPy Lab
Easy
5.
Rahul's function prints the wrong limiting reagent for N₂ + 3H₂ → 2NH₃ with 2.0 mol of nitrogen and… New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by ComputerStemPy LabStemPy Lab
Medium
6.
A lime kiln heats limestone: CaCO₃ → CaO + CO₂. New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by ComputerStemPy LabStemPy Lab
Medium
7.
Zinc reacts with excess hydrochloric acid: Zn + 2HCl → ZnCl₂ + H₂. New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by ComputerStemPy LabStemPy Lab
Hard
8.
Oxalic acid crystals, H₂C₂O₄ · 2H₂O, have a molar mass of 126.07 g/mol. New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by ComputerStemPy LabStemPy Lab
Easy
9.
Two bottles of sodium chloride solution are poured together: 200 mL at 0.5 mol/L and 300 mL at 0.2… New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by ComputerStemPy LabStemPy Lab
Medium
10.
25 mL of 0.05 mol/L sulphuric acid is titrated with 0.1 mol/L sodium hydroxide: H₂SO₄ + 2NaOH →… New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by ComputerStemPy LabStemPy Lab
Hard
11.
Of the first 36 elements, the halogens are fluorine (64 pm), chlorine (99 pm) and bromine (114 pm). New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by Computer, Data Analysis with pandasStemPy LabStemPy Lab
Easy
12.
The first ionisation enthalpies of lithium, sodium and potassium are 520, 496 and 419 kJ/mol. New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by Computer, Data Analysis with pandasStemPy LabStemPy Lab
Medium
13.
A table indexed by symbol is t = df.set_index("symbol"). New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by Computer, Data Analysis with pandasStemPy LabStemPy Lab
Easy
14.
Ravi's program builds the table with the column names symbol, z, group, period, block, radius, ie… New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by Computer, Data Analysis with pandasStemPy LabStemPy Lab
Medium
15.
Rina plots the first ionisation enthalpy against Z for the first 20 elements. New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by Computer, Data Analysis with pandasStemPy LabStemPy Lab
Easy
16.
Across period 3, the atomic radii from sodium to chlorine are 186, 160, 143, 117, 110, 104 and 99… New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by Computer, Data Analysis with pandasStemPy LabStemPy Lab
Medium
17.
A scatter plot of the first 36 elements colours each point by block with df["block"].map(colours). New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by Computer, Data Analysis with pandasStemPy LabStemPy Lab
Easy
18.
Period 2 has two s-block elements, lithium (520) and beryllium (899), and six p-block elements… New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by Computer, Data Analysis with pandasStemPy LabStemPy Lab
Medium
19.
For lithium to fluorine, the radii are 152, 111, 88, 77, 74, 66 and 64 pm, and the first ionisation… New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by Computer, Data Analysis with pandasStemPy LabStemPy Lab
Medium
20.
From gallium to krypton the first ionisation enthalpies are 579, 762, 947, 941, 1140 and 1351… New
High School (11–12), High School (9–10), Undergraduate, General · Chemistry by Computer, Data Analysis with pandasStemPy LabStemPy Lab
Hard
21.
Make a table of the four rocky planets with the columns name, distance_au (0.39, 0.72, 1.00, 1.52)…
High School (11–12), High School (9–10), Undergraduate, General · Data Analysis with pandasStemPy LabStemPy Lab
Easy
22.
A sensor wrote the readings 9.8, 9.7, -999 and 9.9.
High School (11–12), High School (9–10), Undergraduate, General · Data Analysis with pandasStemPy LabStemPy Lab
Medium
23.
Read this CSV text with pd.read_csv: x,y,z then the rows 1,2.0,a and 2,,b and,3.0, and 4,5.0,d.
High School (11–12), High School (9–10), Undergraduate, General · Data Analysis with pandasStemPy LabStemPy Lab
Medium
24.
Make a table of the eight planets with the columns name, kind (the first four are rocky, the last…
High School (11–12), High School (9–10), Undergraduate, General · Data Analysis with pandasStemPy LabStemPy Lab
Medium
25.
In units of the Earth, the density of a planet is its mass divided by the cube of its radius.
High School (11–12), High School (9–10), Undergraduate, General · Data Analysis with pandasStemPy LabStemPy Lab
Medium
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