Which of the following observations led physicist James Chadwick to perform experiments that eventually led to the discovery of the neutron?A. Protons alone were not able to account for the density of an atoms nucleus.
B. Atomic nuclei possess shells similar to the electron shells of atoms.
C. Some atoms contained more protons than electrons.
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Answer 1
Answer:
The correct answer is letter C. James Chadwick confirmed the existence of neutrons.In his experiment, he was able to show that the particles that were ejected had no electrical charge but had almost the same mass as the proton. These particles were, of course, neutrons.
What is the total number of carbon atoms in a molecule of ethanoic acid?(1) 1 (3) 3 (2) 2 (4) 4
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There are 2 carbon atoms in ethanoic acid. Other name of such substance is acetic acid. It is a colorless liquid carboxylic acid with the chemical formula CH3COOH. It has antibacterial and antifungal properties.
What fraction of a Sr-90 sample remains unchanged after 87.3 years
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The answer is 1/8.
Half-life is the time required for the amount of a sample to half its value. To calculate this, we will use the following formulas: 1. , where: n - a number of half-lives x - a remained fraction of a sample
2. where: - half-life t - total time elapsed n - a number of half-lives
The half-life of Sr-90 is 28.8 years. So, we know: t = 87.3 years = 28.8 years
We need: n = ? x = ?
We could first use the second equation, to calculate n: If: , Then:
⇒ ⇒ ⇒ n ≈ 3
Now we can use the first equation to calculate the remained amount of the sample. ⇒ ⇒
When the blood supply to a portion of the brain is blocked, this causesa. a. blackout b. dizzy spells c. stroke d. heart attack
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When blood supply is blocked by a clot in the brain it is called a stroke.
An atom of lithium 7 has an equal number of
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Electrons and protons
Lithium 7 has an equal number of protons and neutrons.
Which of the following is the first step toward proposing solutions effectively?a. Determine the desired outcome.
b. Propose a possible solution.
c. Act on a possible solution.
d. Identify the unresolved problem or dilemma.
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Let's order the four actions in order in which they should be done:
d. Identify the unresolved problem or dilemma. a. Determine the desired outcome. b. Propose a possible solution. c. Act on a possible solution.
Notice how the different steps depend on the previous steps, for example you can only act on the possible solution, once you know what the solution is.
So the first step will be d. Identify the unresolved problem or dilemma.
The correct answer is (d.) Identify the unresolved problem or dilemma. The first step toward proposing solutions effectively is to first identify the unresolved problem or dilemma. Trace all what's causing the problem in order to come up with a resolution.
The strength of a weak base is indicated by its "ionization constant Kb." The greater the value of Kb, the _____ the base. a) Weaker b) Stronger c) More neutral d) Less reactive
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Kb is known as the base dissociation constant and the larger the value of kb the stronger the base. However, at times the values of kb are very small when dealing with calculations of weak bases. Hence, pKb is often used. Pkb = -lg(Kb)