Final answer:
The density of Helga's nickel sample would be 8.9042 g/cm³.
Step-by-step explanation:
The density of a substance is calculated by dividing its mass by its volume. In this case, Rowena has a 5 gram sample of nickel and determines the density to be 8.9 g/cm³. If Helga has a nickel sample that is twice as large and has a mass of 10 grams, we can calculate the density of Helga's sample using the formula:
Density = Mass/Volume
Since the mass of Helga's sample is 10 grams and it is twice as large as Rowena's sample, the volume of Helga's sample would be twice the volume of Rowena's sample. So the volume would be:
Volume of Helga's sample = 2 * 5 g / 8.9 g/cm³ = 1.1236 cm³
Therefore, the density of Helga's sample would be:
Density = Mass/Volume = 10 g / 1.1236 cm³ = 8.9042 g/cm³