1.
What is the most appropriate piece of equipment to accurately measure 85 mL of water?
Correct Answer
B. 100mL measuring cylinder
Explanation
A 100mL measuring cylinder is the most appropriate piece of equipment to accurately measure 85 mL of water because it has a capacity that is closer to the desired volume. Using a measuring cylinder with a smaller capacity, such as a 10mL measuring cylinder, would require multiple measurements and may introduce more error. Similarly, using a larger capacity container, such as a 100mL or 250mL beaker, would make it more difficult to accurately measure the smaller volume of 85 mL.
2.
What is one use of X-rays?
Correct Answer
D. Making images of bones
Explanation
X-rays are commonly used in medical imaging to create images of bones. X-ray machines emit a small amount of radiation that can penetrate through the body and create images of the internal structures. This technique is particularly useful for diagnosing fractures, bone diseases, and monitoring the healing process. By capturing the density variations of the bones, X-rays provide valuable information to healthcare professionals, aiding in the accurate diagnosis and treatment of various bone-related conditions.
3.
What is the smallest unit of an element?
Correct Answer
A. An atom
Explanation
An atom is the smallest unit of an element. It is composed of protons, neutrons, and electrons. Protons and neutrons are located in the nucleus of the atom, while electrons orbit around the nucleus. Each element is made up of a unique number of protons in its nucleus, which determines its atomic number. Therefore, an atom is the fundamental building block of all matter and the smallest unit that retains the chemical properties of an element.
4.
What does the word "combustion" refer to?
Correct Answer
A. The burning of a compound in oxygen
Explanation
The word "combustion" refers to the process of burning a compound in the presence of oxygen. This chemical reaction releases heat and light, and typically produces flames as a result.
5.
The chemical formula for limestone is CaCO3. What is the name of this compound?
Correct Answer
C. Calcium carbonate
Explanation
The correct answer is calcium carbonate. Limestone is a sedimentary rock primarily composed of calcium carbonate. The chemical formula CaCO3 represents one calcium atom bonded to one carbon atom and three oxygen atoms, forming calcium carbonate. Calcium carbon trioxide, calcium carbon oxide, and calcium bicarbonate do not accurately represent the chemical composition of limestone.
6.
What process add carbon dioxide to the atmosphere
Correct Answer
A. Burning, decay and respiration
Explanation
Burning, decay, and respiration are all processes that add carbon dioxide to the atmosphere. Burning releases carbon dioxide when organic materials such as fossil fuels, wood, or plants are combusted. Decay of organic matter also produces carbon dioxide as organic materials break down. Respiration, both by humans and animals, involves the exchange of gases, including the release of carbon dioxide into the atmosphere. Therefore, all three processes contribute to the increase of carbon dioxide in the atmosphere.
7.
Organisms involved in decay are called decomposers. What role do decomposers play in the carbon cycle?
Correct Answer
B. Allow carbon to be reused
Explanation
Decomposers play a crucial role in the carbon cycle by allowing carbon to be reused. When decomposers break down dead organisms and waste materials, they release carbon back into the environment. This carbon can then be used by other organisms for growth and energy. Without decomposers, carbon would remain locked in dead organic matter and unavailable for reuse, disrupting the carbon cycle and limiting the availability of this essential element for other organisms.
8.
Where are protons and neutrons located in atom?
Correct Answer
A. In the nucleus
Explanation
Protons and neutrons are located in the nucleus of an atom. The nucleus is the central part of the atom, consisting of protons and neutrons tightly packed together. This is where most of the mass of the atom is concentrated. The electrons, on the other hand, are located outside the nucleus in the electron cloud, which surrounds the nucleus.
9.
Which process has a role in the growth and repair of tissue in multicellular organisms?
Correct Answer
B. Cell division
Explanation
Cell division is the correct answer because it is the process responsible for the growth and repair of tissues in multicellular organisms. During cell division, a single cell divides into two daughter cells, each with the same genetic material as the parent cell. This allows for the growth of tissues by increasing the number of cells, as well as the repair of damaged or injured tissues by replacing damaged cells with new ones. Coordination, mutation, and sexual reproduction do not directly play a role in the growth and repair of tissues.
10.
The burning of coal in power stations produces carbon dioxide.Which chemical reaction produces the carbon dioxide?
Correct Answer
B. Combustion
Explanation
The burning of coal in power stations is a process known as combustion. During combustion, the carbon present in coal reacts with oxygen in the air to produce carbon dioxide. Therefore, the correct answer is combustion.
11.
What occurs when a new compound is formed?
Correct Answer
D. Atoms are rearranged
Explanation
When a new compound is formed, the atoms involved in the reaction undergo rearrangement. This means that the atoms are reorganized and bonded together in a different arrangement than before. No atoms are lost or destroyed, and new matter is not created. Instead, the existing atoms are rearranged to form the new compound with different chemical properties.
12.
The human stomach contains acid. Sodium bicarbonate (NaHCO3) is often found as a component of antacids, which are used to settle upset stomachs. It reacts in a similar way to normal carbonates, causing people to burp. Why does sodium bicarbonate make people burp?
Correct Answer
C. It produces carbon dioxide gas.
Explanation
Sodium bicarbonate reacts with the acid in the stomach to produce carbon dioxide gas. This gas builds up and creates pressure in the stomach, leading to burping as a way for the body to release the excess gas.
13.
What type of disease is melanoma?
Correct Answer
C. Non-Infectious
Explanation
Melanoma is a type of cancer that develops in the melanocytes, which are the cells that produce melanin. It is not caused by an infection or a contagious agent. Instead, melanoma is primarily caused by exposure to ultraviolet (UV) radiation from the sun or tanning beds, as well as genetic factors. Therefore, it is classified as a non-infectious disease.
14.
Our sun is a medium size star. As it gets older, it will use up its fuel. What is most likely to happen during the next stage of its life?
Correct Answer
B. Expand
Explanation
As the sun gets older and uses up its fuel, it will enter the next stage of its life, which is expansion. This is because as the fuel in the sun's core depletes, the balance between the outward pressure from nuclear fusion and the inward pull of gravity becomes disrupted. The outer layers of the sun will then expand, causing it to become a red giant. Eventually, the sun will shed its outer layers and form a planetary nebula, leaving behind a dense core known as a white dwarf.
15.
A person on Earth has a mass of 100kg. What would their mass be on the moon?
Correct Answer
A. 100kg
Explanation
The mass of an object does not change depending on its location. Therefore, a person's mass on the moon would still be 100kg, the same as on Earth.
16.
Cobalt-60 is commonly used for cancer treatment therapies. How many neutrons are there in an atom of 6027 Co ?
Correct Answer
B. 33
Explanation
Cobalt-60 is an isotope of cobalt that is commonly used in cancer treatment therapies because it emits gamma radiation. The number after the element symbol in the question, 6027Co, represents the atomic mass of cobalt-60. The atomic mass is the sum of the number of protons and neutrons in the nucleus of an atom. Since the atomic mass is 60, and the atomic number (number of protons) for cobalt is 27, we can subtract the atomic number from the atomic mass to find the number of neutrons. Therefore, there are 33 neutrons in an atom of 6027Co.
17.
On what basis are elements arrange from left to right across a row of the Periodic Table?
Correct Answer
A. The atoms gain a proton
Explanation
The periodic table is arranged in increasing atomic number, or the number of protons, from left to right.
18.
An astronomical observatory in Antarctica houses the South Pole Telescope (SPT), which has a diameter of 10 meters. Its location is 9,200 ft above sea level at one of the calmest, coldest places on Earth. Why is this observatory being built in Antarctica?
Correct Answer
B. The atmospHere is unpolluted and will allow clearer images to be obtained.
Explanation
The Pole's high altitude means that the atmosphere is thin, and the extreme cold keeps the amount of water vapor in the air low.
19.
In what way did Dmitri Ivanovich Mendeleev arrange the elements in the periodic table?
Correct Answer
B. By increasing atomic weight and similar properties.
Explanation
Dmitri Ivanovich Mendeleev arranged the elements in the periodic table by increasing atomic weight and similar properties. This means that he organized the elements based on their atomic weights, with the lighter elements coming first and the heavier elements coming later. Additionally, he grouped elements with similar properties together, creating a pattern in the periodic table that allowed for the prediction of undiscovered elements and their properties.
20.
Which is considered the greatest triumph of Mendeleev's periodic table, which earned him the distinction as the "Father of the Modern Periodic Table"?
Correct Answer
D. The prediction of the existence of undiscovered elements.
Explanation
Mendeleev's greatest triumph in the development of the periodic table was his ability to predict the existence of undiscovered elements. By arranging the known elements based on their properties and patterns, Mendeleev was able to identify gaps in the table where elements were missing. He predicted the properties of these missing elements and even left spaces for them in his table. Later, when these elements were discovered and their properties matched Mendeleev's predictions, it provided strong evidence for the accuracy and usefulness of his periodic table. This achievement solidified Mendeleev's reputation as the "Father of the Modern Periodic Table."