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2 years ago

Each element is defined by the number of

Chemistry

2 answers:

Nastasia [14]2 years ago

6 0

Each number is defined by the number of protons.

pentagon [3]2 years ago

4 0

Answer:

The atomic number of an element is equal to the number of protons in each atom and defines the element. For example, all carbon atoms contain 6 protons in their atomic nucleus; so the atomic number of carbon is 6.

What does the number of an element represent?

The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus of every atom of that element. The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus.

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The molar mass of sucrose (C12H22O11) is 342.3 g/mol. A chemist has a 0.500-mol sample of sucrose. What is the mass, in grams, o

Gekata [30.6K]

171 is the answer that I got after my calculations.

8 0

3 years ago

Read 2 more answers

What amount of energy is required to change a spherical drop of water with a diameter of 1.80 mm to three smaller spherical drop

Gekata [30.6K]

This is a straightforward question related to the surface energy of the droplet.

You know the surface area of a sphere is 4π r² and its volume is (4/3) π r³. 

With a diameter of 1.4 mm you have an original droplet with a radius of 0.7 mm so the surface area is roughly 6.16 mm² (0.00000616 m²) and the volume is roughly 1.438 mm³. 

The total surface energy of the original droplet is 0.00000616 * 72 ~ 0.00044 mJ 

The five smaller droplets need to have the same volume as the original. Therefore 

5 V = 1.438 mm³ so the volume of one of the smaller spheres is 1.438/5 = 0.287 mm³. 

Since this smaller volume still has the volume (4/3) π r³ then r = cube_root(0.287/(4/3) π) = cube_root(4.39) = 0.4 mm. 

Each of the smaller droplets has a surface area of 4π r² = 2 mm² or 0.0000002 m². 

The surface energy of the 5 smaller droplets is then 5 * 0.000002 * 72.0 = 0.00072 mJ 
From this radius the surface energy of all smaller droplets is 0.00072 and the difference in energy is 0.00072- 0.00044 mJ = 0.00028 mJ. 

Therefore you need roughly 0.00028 mJ or 0.28 µJ of energy to change a spherical droplet of water of diameter 1.4 mm into 5 identical smaller droplets.

7 0

3 years ago

2. Potassium is a metal with one valence electron. With which other elements does it form bonds? a elements with one electron b.

Anika [276]

Answer:

Atoms with one or two valence electrons more than a closed shell are highly reactive ... Hydrogen can form bonds to many other elements such as nitrogen NH 3 ... the electron dot structure and iii the chemical K 1 valence electron 1 dot K . B two. ... The alkaline earth metals IIA elements lose two electrons to form a 2 cation.

Explanation:

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2 years ago

Use this information to determine the number of valence electrons in the atoms. Which of the following correctly compares the st

vlabodo [156]

The question is incomplete. The complete question is :

The table compares the number of electrons in two unknown neutral atoms.

Comparison of Electrons

Atom Number of Electrons

A 9

D 11

Use this information to determine the number of valence electrons in the atoms. Which of the following correctly compares the stability of the two atoms?

A. Both are unreactive.

B. Both are highly reactive.

C. A is unreactive and D is reactive.

D. A is reactive and D is unreactive.

Answer:

B. Both are highly reactive.

Explanation:

Atomic number of electrons given is 9 and 11, it means that atom A is fluorine (F) and atom D is Sodium (Na).

In order to gain stability 8 electrons are required in outer shell. So atoms either gain or lose electrons in its outer shell to become more reactive.

Sodium has electronic configuration (2,8,1) and easily loses one electron and become (2, 8) which is highly reactive.

Fluorine has electronic configuration (2, 7) and can gain easily an electron and becomes reactive to form (2, 8).

So, both they both attain stability by losing and gaining only one electron.

Hence, they both are highly reactive and the correct option is B.

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3 years ago

Look back at your data and your regression equation. (Sample data is shown to the right, with X= pressure and Y=volume.) click a

laiz [17]

Select the block of cells to be included in the scatter plot by clicking and dragging, then from the Insert ribbon under Chart drop down the Scatter or Bubble menu and select Scatter. A chart will appear on the spreadsheet.

To set up a scatter plot in Excel, enter the pairs of data in two columns with each value of a pair on the same row. By default, Excel considers the column on the left to contain the horizontal (X) values and the column on the right to contain the vertical (Y) values.

If you click on the + sign at the upper right of the chart, a list of checkboxes will appear. Check Axes, Axis Titles, and Trendline. Uncheck everything else. You should edit the Axis Titles to include the name of the factor and any units associated with it. Double-click on the Axis numbers to bring up the Format Axis dialog, then click on the bar-graph icon to access Axis Options. Set the bounds and units appropriately and set the tick marks to something sensible.

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3 years ago

Each element is defined by the number of​

Each element is defined by the number of