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AQA · GCSE · Chemistry · Higher

Estimating krypton density from a graph

Q02.5 1 mark

Table 1 shows the densities of some of the elements in Group 0 of the periodic table.

Table 1
ElementAtomic numberDensity in mg/cm³
Helium20.2
Neon100.8
Argon181.6
Krypton36X
Xenon545.4
Radon869.1
Figure 1
Figure 1

Figure 1

Enlarged question image

Figure 1

Estimate the density (X) of krypton. Use Figure 1 and Table 1.

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Marking points

  1. 1 Density estimate is in the inclusive range 3.0–3.8 mg/cm³.

Full-mark answer

At atomic number 36, the plotted trend gives a density of approximately 3.4 mg/cm³ (3.0–3.8 mg/cm³ is accepted).

Why this answer loses marks

I copied the density of the nearest plotted element.

Estimate at the requested horizontal position from the trend, rather than copying an existing row.

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