Tutor profile: Shanon Q.
Find the molarity of 45.5g of CaCl2 in 500mL of solution.
First of, the formula for Molarity = moles of solute / volume of solution measured in L. Therefore, the first thing to do is convert 45.5g of CaCl2 to moles. 45.5g CaCl2 x 1mol CaCl2/ 110.98 g CaCl2 (this number is found on the periodic table through molar mass) = 0.41 mol Now, convert 500mL to L by dividing by 1000 = .5L Lets plug it into the equation for Molarity = 0.41mol/.5L = 0.82M
How are variations created in the genes?
Variations occur at the most molecular level of an organism: meiosis. Meiosis is the process of replication that makes a diploid (46 chromosomes in the human) to a haploid (23 chromosomes in the human). Variation occurs during Prophase I where crossing over occurs. This is when 2 homologous pair exchange genetic information. They attach at the synapse and exchange information to form a chiasmata. This is one of the simple and basic ways of exchanging information for variation. It is not the only way.
Subject: Basic Chemistry
What is the polarity of the structure of CCl4?
First, what do we know about polarity? On the most basic terms, let me give you an analogy: imagine 2 children of equal weight sitting on a teeter totter, is the teeter totter balanced? (student answers: yes) The teeter totter is the bond between the 2 elements and the children are the elements. Lets say you have an adult and a child on the teeter totter, is it balanced? (student answers:no) So in simple terms, balanced meaning they are the SAME element is non polar and different element is polar. Thinking of that definition, is C-Cl bond polar or non polar? (student answers: polar). Good job! But what is the question asking for? if the STRUCTURE is polar. Structure is dependent on symmetry. So, if we were to draw out the Lewis structure for CCl4, it would like an equal cross, is that symmetric? (student answers: yes). So if the structure is non polar, it overrides the bond polarity making the entire struture polar.
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