Question

mid year practice

1. matter and energy can neither be created nor destroyed. what happens to energy and matter when an

organism is eaten? food web
energy and matter are moved to the ocean\tenergy and matter are stored as fossil fuels
energy and matter are released into the atmosphere\tenergy and matter move to the consumer

1. density is the ratio of mass to volume. devon recorded the density of four metals at a temperature of 20

degrees celsius.
material\tdensity (g/cm3)
brass\t8.9
gold\t19.3
iron\t7.8
lead\t11.3
if devon has a 4cm cube of each of these metals, which cube will have the greatest mass? physical properties
brass\tgold\tiron\tlead

1. some mixtures are classified as acids or bases. the ph scale shows how acidic or how basic these compounds

are. vinegar, a common cleaning agent, has a ph of about 2.2.
ph scale image
which phrase describes vinegar? ph scale
highly acidic\thighly basic\tslightly acidic\tslightly basic

1. all matter has both physical and chemical properties. a physical property can be observed without changing

the identity of the substance. which is a physical property? physical/chemical properties
ability to rust\tdensity\tflammability\treactivity with water

Explanation:

Question 23

In a food web, when an organism is eaten, the energy and matter from the prey (the eaten organism) are transferred to the predator (the consumer). The other options are incorrect: moving to the ocean is not a general outcome, storing as fossil fuels is a long - term geological process not related to immediate consumption, and releasing into the atmosphere is more related to processes like respiration or decomposition rather than consumption.

Step1: Recall the formula for mass

The formula that relates density ($
ho$), mass ($m$), and volume ($V$) is $m=
ho\times V$.

Step2: Calculate the volume of the cube

The volume of a cube is given by the formula $V = s^3$, where $s$ is the side length of the cube. Here, $s = 4\space cm$, so $V=(4)^3=64\space cm^3$.

Step3: Analyze the relationship between density and mass

Since the volume $V = 64\space cm^3$ is the same for all the metal cubes (as each is a $4\space cm$ cube), the mass $m$ is directly proportional to the density $
ho$ (because $m=
ho\times V$ and $V$ is constant). So, the metal with the highest density will have the greatest mass.
Looking at the density values: brass has a density of $8.9\space g/cm^3$, gold has a density of $19.3\space g/cm^3$, iron has a density of $7.8\space g/cm^3$, and lead has a density of $11.3\space g/cm^3$. Among these, gold has the highest density.

The pH scale ranges from 0 to 14. A pH value less than 7 indicates an acidic substance, and the lower the pH value, the more acidic the substance is. Vinegar has a pH of about 2.2, which is much less than 7 and is relatively low on the pH scale (close to 0 - 3 which are highly acidic substances like battery acid). So, vinegar is highly acidic. A pH above 7 is basic, so the "highly basic" and "slightly basic" options are incorrect. A slightly acidic substance would have a pH closer to 7 (e.g., around 5 - 6), but vinegar's pH of 2.2 is much lower, so it is not slightly acidic.

Answer:

Energy and matter move to the consumer

Question 24