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3 years ago

Can somebody plz help with Grade7science!!

Chemistry

1 answer:

Igoryamba3 years ago

7 0

Solar energy has been proven to be the most efficient and effective among renewable energy sources for home and commercial use.

Hope this helpes UwU

You might be interested in

Look at this graph:

Rufina [12.5K]

Y= Mx + b
So it’s 3/2

8 0

3 years ago

1.Draw the skeletal structures of two different molecules that are each made of 5 carbon atoms and 12 hydrogen atoms then Name t

mihalych1998 [28]

Answer:

How many of each kind of atom is in one molecule of water? 1 hydrogen atom and 2 oxygen atoms 1 hydrogen atom and 1 oxygen atom 2 hydrogen atoms and 1 oxygen atom 2 hydrogen atoms and 2 oxygen atoms

Explanation:

1.Draw the skeletal structures of two different molecules that are each made of 5 carbon atoms and 12 hydrogen atoms then Name the two molecules you drew.

7 0

3 years ago

Following the instructions in your lab manual, you have titrated a 25.00 mL sample of 0.0100 M KIO3 with a solution of Na2S2O3 o

vivado [14]

Answer:

For 1: The amount of potassium iodate that were titrated is $2.5\times 10^{-4}$ moles

For 2: The amount of sodium thiosulfate required is $1.25\times 10^{-4}$ moles

Explanation:

For 1:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in L)}}$

Molarity of $KIO_3$ solution = 0.0100 M

Volume of solution = 25 mL

Putting values in above equation, we get:

$0.0100M=\frac{\text{Moles of }KIO_3\times 1000}{25}\\\\\text{Moles of }KIO_3=\frac{0.0100\times 25}{1000}=0.00025mol$

Hence, the amount of potassium iodate that were titrated is $2.5\times 10^{-4}$ moles

For 2:

The chemical equation for the reaction of potassium iodate and sodium thiosulfate follows:

$2KIO_3+Na_2S_2O_3\rightarrow K_2S_2O_3+2NaIO_3$

By Stoichiometry of the reaction:

2 moles of potassium iodate reacts with 1 mole of sodium thiosulfate

So, 0.00025 moles of potassium iodate will react with = $\frac{1}{2}\times 0.00025=0.000125mol$ of sodium thiosulfate

Hence, the amount of sodium thiosulfate required is $1.25\times 10^{-4}$ moles

6 0

3 years ago

___AsCl3+____H2S-->___As2S3+___HCI

Alex17521 [72]

Answer:

2 AsCl₃ + 3 H₂S → As₂S₃ + 6 HCl

Explanation:

When we balance a chemical equation, what we are trying to do is to achieve the same number of atoms for each element on both sides of the arrow. On the right of the arrow is where we can find the products, while the reactants are found on the left of the arrow.

We usually balance O and H atoms last.

AsCl₃ + H₂S → As₂S₃ +HCl

reactants

As --- 1

Cl --- 3

H --- 2

S --- 1

products

As --- 2

Cl --- 1

H --- 1

S --- 3

2 AsCl₃ + H₂S → As₂S₃ +HCl

reactants

As --- 2

Cl --- 6

H --- 2

S --- 1

products

As --- 2

Cl --- 1

H --- 1

S --- 3

The number of As atoms is now balanced.

2 AsCl₃ + 3 H₂S → As₂S₃ +HCl

reactants

As --- 2

Cl --- 6

H --- 6

S --- 3

products

As --- 2

Cl --- 1

H --- 1

S --- 3

The number of S atoms is now equal on both sides.

2 AsCl₃ + 3 H₂S → As₂S₃ + 6 HCl

reactants

As --- 2

Cl --- 6

H --- 6

S --- 3

products

As --- 2

Cl --- 6

H --- 6

S --- 3

The equation is now balanced.

3 0

3 years ago

Some radioactive nuclides have very short half-lives, for example, I-31 has a half-life of approximately 8 days. Pu-234, by comp

lorasvet [3.4K]

Answer:

Here's what I find.

Explanation:

Iodine-131

Iodine-131 is both a beta emitter and a gamma emitter.

$_{53}^{131}\text{I}\longrightarrow \, _{54}^{131}\text{Xe} +\, _{-1}^{0}\text{e} +\, _{0}^{0}\gamma$

About 90 % of the energy is β-radiation and 10 % is γ-radiation. Both forms are highly energetic.

The main danger is from ingestion. The iodine concentrates in thyroid gland, where the β-radiation destroys cells up to 2 mm from the tissues that absorbed it.

Both the β- and γ-radiation cause cell mutations that can later become cancerous. Small doses, such as those absorbed from the nuclear disasters in the Ukraine and Japan, can cause cancers years after the original iodine has disappeared.

Plutonium-239

Plutonium-239 is an alpha emitter.

$_{94}^{239}\text{U} \longrightarrow \, _{92}^{235}\text{Xe} + \, _{2}^{4}\text{He}$

Alpha particles cannot penetrate the skin, so external exposure isn't much of a health risk.

However, they are extremely dangerous when they are inhaled and get inside cells. They travel first to the blood or lymph system and later to the bone marrow and liver, where they cause up to 1000 times more chromosomal damage than beta or gamma rays.

It takes about 20 years for plutonium to be eliminated from the liver around 50 years for from the skeleton, so it has a long time to cause damage.

6 0

4 years ago