Exams & Certification
How many core and valence electrons does one atom of magnesium (Mg) have? 2 core and 10 valence 6 core and 6 valence 10 core and 2 valence 4 core and 8 valence The Correct Answer and Explanation is: Correct Answer: 10 core and 2 valence Magnesium (Mg) has an atomic number of 12, indicating […]
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Which of the following is a rational number? Square root of 23 Square root of 22 Square root of 24 Square root of 25 The Correct Answer and Explanation is: Correct Answer: Square root of 25 A rational number is any number that can be expressed as a ratio of two integers, written in the
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Why is the square root of 23 an irrational number The Correct Answer and Explanation is: The square root of 23 is an irrational number because it cannot be expressed as a ratio of two integers. In other words, there are no two integers aaa and bbb such that 23=ab\sqrt{23} = \frac{a}{b}23=ba, where b≠0b \ne
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What is the first step in the mechanism of the dehydration of 2-methyl-2-pentanol? The removal of a β-hydrogen from the alcohol The loss of OH- to form a carbocation The protonation of the hydroxyl group The loss of the proton from the hydroxyl group to give an alkoxide ion The Correct Answer and Explanation is:
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The price of a hotel room in Helsinki is 159 euros/night. The exchange rates are 1 EUR = 1.0819 USD and 1 USD = 0.7732 GBP. Calculate the price of the room in British pounds (GBP). (EUR = euro, USD = American dollar, GBP = British pound) 2. Corrected_text: A company’s costs are divided into
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If a person weighs 133 lbs and is 5’2″ tall, what is their height in meters and weight (mass) in kg? Show work using dimensional analysis and give answers with correct sig figs and units. Calculation of height in meters (m): To convert feet to meters, we use the conversion factor 1 ft = 0.3048
Which is the strongest base, NaOH or Ba(OH)2? Also, mention the reason. The Correct Answer and Explanation is: Correct Answer:Ba(OH)₂ is the stronger base compared to NaOH. Explanation A base is considered strong when it dissociates completely in water to produce hydroxide ions (OH⁻). Both sodium hydroxide (NaOH) and barium hydroxide (Ba(OH)₂) are classified as
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Factor x2 – 5x – 6. The Correct Answer and Explanation is: Correct Answer:The expression x2−5x−6x^2 – 5x – 6×2−5x−6 factors to:(x−6)(x+1)(x – 6)(x + 1)(x−6)(x+1) ExplanationThe given quadratic expression is in standard form:x2−5x−6x^2 – 5x – 6×2−5x−6 This expression can be factored by finding two numbers that multiply to the constant term, −6-6−6, and
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The factorisation of – x2 + 5x – 6 yields (a) – (x – 2)(3 – x) (b) – (2 – x) (3 – x) (c) (x – 2)(x – 3) (d) (2 + x) (3 – x) The Correct Answer and Explanation is: The correct answer is: (b) – (2 – x)(3 – x)
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Write out the chemical reaction whose enthalpy is the heat of fusion of sodium chloride, NaCl The Correct Answer and Explanation is: Correct Chemical Reaction (Heat of Fusion of NaCl): NaCl(s)→NaCl(l)\text{NaCl(s)} \rightarrow \text{NaCl(l)}NaCl(s)→NaCl(l) Explanation The heat of fusion refers to the amount of energy required to change a substance from the solid phase to the