3.1 Changes of state and the particle model

A student is carrying out an experiment to determine the density of an obsidian glass sphere.

The student measures the volume of the sphere by displacement of water in a measuring cylinder. The results are shown in Table 1.

Table 1

Volume of water ( $cm3\text{cm}^3$ )	Volume of water and sphere ( $cm3\text{cm}^3$ )	Volume of sphere $Y$ ( $cm3\text{cm}^3$ )
$35.2$	$41.8$	$Y$

Calculate the volume of the sphere, $Y$ , in Table 1.

[1]

The student noticed that the digital balance had a zero error: it displayed a reading of $g-0.12\text{ g}$ before any object was placed on it.

How should the student correct this error after the mass of the sphere has been measured?

[1]

A different obsidian specimen has a volume of $cm31.85\text{ cm}^3$ . The density of this obsidian is $g/cm32.40\text{ g/cm}^3$ .

Calculate the mass of this different specimen in grams. State the formula you used to link density ( $ρ\rho$ ), mass ( $m$ ), and volume ( $V$ ).

[2]