5. the 7th hr class produced the graph below when they plotted mass vs. volume for samples of two…

5. the 7th hr class produced the graph below when they plotted mass vs. volume for samples of two substances.\nfig 4\n80\n70\nsubstance a\n60\n50\nmass (g)\n40\n30\n20\nsubstance b\n10\n0\n10 20 30 40 50 60 70 80\nvolume (ml)\n\na. write the equation of the line for substance b.\n\nb. how does substance b differ from substance a?\n\nc. calculate the mass of a 35.0 cm³ piece of substance b.\n\nd. what would occupy a larger volume: 100 g of substance a or 100 g of substance b? explain.\n\ne. use a particle diagram to show the difference in density between the two substances.
Answer
Explanation:
Step1: Find the slope and y - intercept for substance B
The graph of substance B is a straight - line passing through the origin (0,0). The slope $m$ of a line passing through two points $(x_1,y_1)$ and $(x_2,y_2)$ is given by $m=\frac{y_2 - y_1}{x_2 - x_1}$. Taking two points on the line of substance B, say (0,0) and (80,40), the slope $m=\frac{40 - 0}{80 - 0}=\frac{1}{2}$. The equation of a line in slope - intercept form is $y = mx + b$, where $b$ is the y - intercept. Since the line passes through the origin, $b = 0$. So the equation for substance B is $y=\frac{1}{2}x$, or in terms of mass $m$ and volume $V$, $m=\frac{1}{2}V$.
Step2: Compare the lines of substance A and B
The slope of the line for substance A is steeper than that of substance B. The slope of a mass - volume graph represents density ($\rho=\frac{m}{V}$). So substance A has a higher density than substance B.
Step3: Calculate the mass of a 35.0 $cm^3$ piece of substance B
Using the equation $m=\frac{1}{2}V$, substitute $V = 35.0\ cm^3$. Then $m=\frac{1}{2}\times35.0\ g=17.5\ g$.
Step4: Determine which substance occupies a larger volume for 100 g
For substance A, let its density be $\rho_A$ and for substance B, $\rho_B$. Since $\rho_A>\rho_B$ (from the steeper slope of A's graph), and using the formula $V=\frac{m}{\rho}$, for a given mass $m = 100\ g$, the volume $V$ is inversely proportional to the density. So 100 g of substance B will occupy a larger volume than 100 g of substance A.
Step5: Particle diagram concept
In a particle diagram for density comparison, for substance A (higher density), the particles would be more closely packed together, while for substance B (lower density), the particles would be more spread out.
Answer:
a. $m=\frac{1}{2}V$ b. Substance A has a higher density than substance B (steeper slope of its mass - volume graph). c. 17.5 g d. 100 g of substance B would occupy a larger volume because substance B has a lower density than substance A. e. In the particle diagram, particles of substance A are more closely packed, while particles of substance B are more spread out.