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defon
3 years ago
8

Please help with both

Chemistry
1 answer:
kupik [55]3 years ago
8 0

Answer:

D =Average atomic mass  = 10.801 amu.

5) True

Explanation:

Abundance of B¹⁰= 19.9%

Abundance of B¹¹ = 80.1%

Atomic mass of B¹⁰ = 10 amu

Atomic mass of B¹¹ = 11 amu

Average atomic mass = ?

Solution:

Average atomic mass  = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

Average atomic mass  = (10×19.9)+(11×80.1) /100

Average atomic mass =  199 + 881.1 / 100

Average atomic mass  = 1080.1 / 100

Average atomic mass  = 10.801 amu.

2)A chemical reaction is one in which a new elements is created

True

False

Answer:

In chemical reaction new substances are created.

For example:

Photosynthesis:

It is the process in which in the presence of sun light and chlorophyll by using carbon dioxide and water plants produce the oxygen and glucose.

Carbon dioxide + water + energy →   glucose + oxygen

water is supplied through the roots, carbon dioxide collected through stomata and sun light is capture  by chloroplast.

Chemical equation:

6H₂O + 6CO₂ + energy  →   C₆H₁₂O₆ + 6O₂

it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water and created one mole of glucose and six mole of oxygen.

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The correct lewis structure for COH2 contains how many covalent bonds?
VARVARA [1.3K]

Answer:

Four covalent bonds.

Explanation:

Hello,

In this case, given the attached picture in which you can find the Lewis dot structure for metanal (formaldehyde) we can see two C-H bonds and two C-O bonds via a double bond, thus, we can compute the type of each bond given the electronegativities of hydrogen, carbon and oxygen which are 2.1, 2.5 and 3.5 respectively:

C-H=2.5-2.1=0.4\\C-O=3.5-2.5=1.0

Thus, since both electronegativity difference are less 1.7 we infer that all of them are covalent, therefore, it has four covalent bonds, two C-H bonds and a double C-O bond.

Best regards-

8 0
3 years ago
ASAP: The main difference between the gravitational force and electrical force is that
Dahasolnce [82]

Answer:

Electrical force can pull and push

Explanation:

5 0
3 years ago
Which of the following is true of the water molecule?
Yuki888 [10]
The Answer To This Is B.
7 0
3 years ago
How many grams of mercury can be produced if 18.0 g of mercury (11) oxide decomposes?
NARA [144]

Answer:

18.0 g of mercury (11) oxide decomposes to produce 9.0 grams of mercury

Explanation:

Mercury oxide has molar mass of 216.6 g/ mol. It gas a molecular formula of HgO.

The decomposition of mercury oxide is given by the chemical equation below:

2HgO ----> 2Hg + O₂

2 moles of HgO decomposes to produce 1 mole of Hg

2 moles of HgO has a mass of 433.2 g

433.2 g of HgO produces 216.6 g of Hg

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Therefore, 18.0 g of mercury (11) oxide decomposes to produce 9.0 grams of mercury

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