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gladu [14]
3 years ago
11

Write the symbol for every chemical element that has atomic number greater than 55 and atomic mass less than 144.0 u

Chemistry
1 answer:
laila [671]3 years ago
3 0
You will need a periodic table to help you answer this problem. The atomic numbers are arrange from lowest to highest in the periodic table. You can locate element number 55 to be Cesium with an atomic weight of 132.905 amu. So, you start from element 56. The following elements are:

56     Barium       137.328 amu
57     Lanthanium   138.905 amu
58     Cerium       140.116 amu
59     <span>Praseodymium    140.908 amu
60     Neodymium   144.243 amu

Neodymium is already greater than 144 amu. Therefore, these elements only include Barium, Lanthanium, Cerium and Praseodymium.</span>
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kodGreya [7K]

Answer:

See explanation

Explanation:

9g of water contains : 9g/18 g/mol = 0.5 mole of water

1) 2 moles of hydrogen yields 2 moles of water

x moles of hydrogen yields 0.5 moles of water

x= 2 × 0.5/2 = 0.5 moles of hydrogen

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2 moles of Al(OH)3 yields 3 moles of H2O

6 moles of Al(OH)3 yields 6 × 3/2 = 9 moles of H20

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Mass of each oxygen atom = 16 g

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A mixture contains 95% sulfutic acid how many grams of mixture are needed to get 100g H2so4
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Answer:

Explanation:

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How much heat must be removed from 456 g of water at 25.0°c to change it into ice at?
N76 [4]
This question can be simply solved by using heat formula,
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C = Specific heat capacity (J / kg K)
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hence the temperature change is 25 K (298 K - 273 K)
C for water is 4186 J / kg K or 4.186 J / g K
By applying the equation,
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Explanation:

I hope this helps!! Pls give brainliest!! :)

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