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mylen [45]
2 years ago
5

Danny sails a boat downstream. The wind pushes the boat along at 21 km/hr. The current runs downstream at 15 km/hr. What is the

actual velocity of the boat?
A) 6.0 km/hr, downstream
B) 1.4 km/hr, downstream
C) 310 km/hr, downstream
D) 36 km/hr, downstream
Chemistry
2 answers:
deff fn [24]2 years ago
7 0

Answer: D) 36.0 km/hr, downstream

Explanation:

For downstream motion of the boat, the actual velocity of the boat is the sum of velocity of the water current and the velocity of the boat due to pushed by wind.

Velocity of water current, v = 15 km/h

Velocity of the boat going downstream, u = 21 km/h

Actual velocity of the boat = v'

v' = v + u

⇒v' = 15 km/h + 21 km/h

⇒u = 21 km/h +15 km/h = 36.0 km/h downstream

Thus, the correct answer is option D.

natali 33 [55]2 years ago
4 0
D. 36 km/hr, downstream

you add the boats speed of 21kph to the rivers speed of 15kph to get your answer
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Hafnium has six naturally occurring isotopes: 0.16% of 174Hf, with an atomic weight of 173.940 amu; 5.26% of 176Hf, with an atom
ser-zykov [4K]

Answer:

177.277amu

Explanation:

the total occuring isotopes for Hafnium is =6.

First isotope had an atomic weight of 173.940amu

Second isotope =175.941amu

Third isotope =176.943amu

Fourth isotope=177.944amu

Fifth isotope. =178.946amu

sixth isotope .179.947amu

<em>Avera</em><em>ge</em><em> </em><em>ato</em><em>mic</em><em> </em><em>wei</em><em>ght</em><em> </em><em>of</em><em> </em><em>Haf</em><em>nium</em><em>=</em><em> </em><em>sum</em><em> </em><em>of</em><em> </em><em>all</em><em> </em><em>the </em><em>atomi</em><em>c</em><em> </em><em>weights</em><em> </em><em>of</em><em> </em><em>the</em><em> </em><em>iso</em><em>topes</em><em>/</em><em> </em><em>Tota</em><em>l</em><em> </em><em>occu</em><em>ring</em><em> </em><em>isotopes</em>

Thus, 173.940amu+175.941amu+176.943amu+177.944amu+178.946amu+179.947amu.= 1063.661amu

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6 0
2 years ago
Give four different chemical meanings for the word element and an example of each
Naddika [18.5K]

Answer ;

-An element is a substance containing only one type of atom, for example; H2 or 02  (consisting of atoms that all have the same number of protons).

-Microscopic, single atom of that element

-Macroscopic, sample of that element large enough to weigh on a balance

- A substance that cannot be broken down chemically; e.g; sodium metal,

Explanation;

-An element is a substance whose atoms all have the same number of protons: another way of saying this is that all of a particular element's atoms have the same atomic number. Elements are chemically the simplest substances and hence cannot be broken down using chemical reactions.

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3 0
2 years ago
Drinking water may contain a low concentration of lead ion (Pb2 ) due to corrosion of old lead pipes. The EPA has determined tha
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Answer:

3.861x10⁻⁹ mol Pb⁺²

Explanation:

We can <u>define ppm as mg of Pb²⁺ per liter of water</u>.

We<u> calculate the mass of lead ion in 100 mL of water</u>:

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Now we <u>convert mass of lead to moles</u>, using its molar mass:

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2 years ago
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Fynjy0 [20]
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kolbaska11 [484]

Answer:

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From Avogadro's law

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6 0
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