Question

check for understanding
use your understanding of density to complete the activities.
what is it? an unknown fluid substance has a mass of 5 grams and a volume of 7 milliliters. which of the following items is a possible identity of the substance?
a. lamp oil, 0.2 g/ml
b. vegetable oil, 0.71 g/ml
c. honey, 1.3 g/ml
d. dish soap, 1.7 g/ml
identifying substances by density the densities of three metals are shown:

• iron, 7.8 g/ml
• tin, 7.3 g/ml
• titanium, 4.5 g/ml

determine the identities of the unknown samples based on their densities.
iron tin titanium

1. sample a: 225 grams, 50 milliliters __________
2. sample b: 365 grams, 50 milliliters __________
3. sample c: 780 grams, 100 milliliters __________

Explanation:

Part 1: Identifying the fluid substance

Step 1: Recall the density formula

Density is calculated using the formula $
ho = \frac{m}{V}$, where $m$ is mass and $V$ is volume.

Step 2: Calculate the density of the unknown fluid

Given $m = 5$ grams and $V = 7$ milliliters, the density $
ho=\frac{5}{7}\approx0.71$ g/mL.

Step 3: Compare with the given options

We compare the calculated density (≈0.71 g/mL) with the densities of the options. Option B (vegetable oil, 0.71 g/mL) matches.

Step 1: Use the density formula

$
ho = \frac{m}{V}$, where $m = 225$ g and $V = 50$ mL.

Step 2: Calculate the density

$
ho=\frac{225}{50} = 4.5$ g/mL.

Step 3: Match with the metal densities

The density 4.5 g/mL matches titanium's density.

Step 1: Apply the density formula

$
ho = \frac{m}{V}$, with $m = 365$ g and $V = 50$ mL.

Step 2: Compute the density

$
ho=\frac{365}{50}=7.3$ g/mL.

Step 3: Identify the metal

This density (7.3 g/mL) matches tin's density.

Answer:

B. vegetable oil, 0.71 g/mL

Part 2: Identifying the metal samples

1. Sample A: 225 grams, 50 milliliters