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kakasveta [241]
3 years ago
15

How many dots are shown in the electron dot diagram for calcium, element number 20?

Chemistry
1 answer:
kykrilka [37]3 years ago
4 0
2 dots  are shown for drawing it. because it has two valence electrons
           
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The mass of water in a single popcorn kernel was found to be 0.905 grams after it popped at a temperature of 175 °C. Using the i
Rus_ich [418]

Answer:

0.583 kilojoules

Explanation:

The amount of heat required to pop a single kernel can be calculated using the formula as follows:

Q = m × c × ∆T

Where;

Q = amount of heat (J)

m = mass of water (g)

c = specific heat capacity of water (4.184 J/g°C)

∆T = change in temperature

From the given information, m = 0.905 g, initial temperature (room temperature) = 21°C , final temperature = 175°C, Q = ?

Q = m × c × ∆T

Q = 0.905 × 4.184 × (175°C - 21°C)

Q = 3.786 × 154

Q = 583.044 Joules

In kilojoules i.e. we divide by 1000, the amount of heat is:

= 583.04/1000

= 0.583 kilojoules

8 0
3 years ago
The heat of vaporization of water is 40.66 kJ/mol. How much heat is absorbed when 3.11 g of water boils at atmospheric pressure?
Roman55 [17]

Answer:

The amount of heat that is absorbed when 3.11 g of water boils at atmospheric pressure is 7.026 kJ.

Explanation:

A molar heat of vaporization of 40.66 kJ / mol means that 40.66 kJ of heat needs to be supplied to boil 1 mol of water at its normal boiling point.

To know the amount of heat that is absorbed when 3.11 g of water boils at atmospheric pressure, the number of moles represented by 3.11 g of water is necessary. Being:

  • H: 1 g/mole
  • O: 16 g/mole

the molar mass of water is:

H₂O= 2* 1 g/mole + 16 g/mole= 18 g/mole

So: if 18 grams of water are contained in 1 mole, 3.11 grams of water in how many moles are present?

moles of water=\frac{3.11 grams*1 mole}{18 gramos}

moles of water= 0.1728

Finally, the following rule of three can be applied: if to boil 1 mole of water at its boiling point it is necessary to supply 40.66 kJ of heat, to boil 0.1728 moles of water, how much heat is necessary to supply?

heat=\frac{0.1728 moles*40.66 kJ}{1 mole}

heat= 7.026 kJ

<u><em>The amount of heat that is absorbed when 3.11 g of water boils at atmospheric pressure is 7.026 kJ.</em></u>

7 0
3 years ago
This nonmetal is in the same group as lead.<br><br> What is the element
Andreyy89
Lead<span> (/lɛd/) is a chemical </span>element<span> in the carbon </span>group<span> with symbol Pb (from Latin: plumbum) and atomic </span>number<span> 82. 

~ I don't know if this will help, but I hope it does. ~</span>
5 0
4 years ago
A theory is a ___.
Dimas [21]

The answer is either A or C. Sorry I'm not much help :)

7 0
4 years ago
Which physical property is used to be Indentify the ability to dissolve
natulia [17]

Answer:

solubility

Explanation:

solubility is a measure of how much a substance will dissolve in a solvent.

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3 years ago
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