Tutor profile: Benjamin W.
The circumference of the Earth is approximately 40,000km. What is its approximate surface area in sq km?
Convert circumference to diameter by dividing it by pi. Then convert the diameter to its radius by dividing by 2. From there, use the formula for a surface area of a sphere: 4(pi)r^2 to get approximately 5.10*10^8 sq km (or 509,295,818 sq km).
Subject: Basic Chemistry
You have a flask containing 27g of liquid ethanol and decide to ignite it, thereby converting ethanol and oxygen into carbon dioxide and water. After balancing the chemical equation, use stoichiometry to determine how many grams of water should be in the flask, assuming all of the ethanol combusted and no water left in the form of vapor.
Convert grams of ethanol to moles of ethanol, and use the equation to convert how many moles of water that is (mol EtOH * 3). Multiply the number of moles of water by the molar mass of water, and you should get approximately 31.67g (or 32g if you stick to the rule of significant figures).
In order, list out the phases of somatic cell division and provide a description for each (pictures and labels are acceptable, but I will ask for you to describe what is occurring in each picture). If you find this to be difficult, create a mnemonic device to help you remember the order.
Interphase: Cell carries out usual functions. Prophase: Chromosomes condense and enzymes break down the nuclear envelope, including the nucleolus. Prometaphase: Centrioles at the poles of the cell produce spindle fibers of tubulin that attach to the centromeres of the chromosomes. (I've never seen high schoolers or non-bio majors have to know this one) Metaphase: Chromosomes are moved by the spindle fibers to be aligned at the center of the cell. Anaphase: Sister chromatids are pulled apart to either pole of the cell. Telophase: Once each side of the cell has one copy of each chromosome, the spindle fibers break down, two nuclei develop, and the cell begins to divide into two. Cytokinesis: A contractile ring of filamentous actin ultimately separates the cell into two independent daughter cells, which continue into interphase. Example of mnemonic device: - I - Punch - Police - Men - At - The - Courthouse
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