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MariettaO [177]
4 years ago
5

The​ half-life of a radioactive substance is 28.1 years.

Chemistry
2 answers:
morpeh [17]4 years ago
7 0

Answer:

In the blue area, people live closely because of its 1.Indutrialised area 2. The land is costly. 3.urbanisation In lighter color areas its farther because 1.Village 2.Farming area 3.Less popular rural area

Explanation:

In the blue area, people live closely because of its 1.Indutrialised area 2. The land is costly. 3.urbanisation In lighter color areas its farther because 1.Village 2.Farming area 3.Less popular rural area

dusya [7]4 years ago
5 0
Hopefully this will help you.

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A hydrated salt is a solid that includes water molecules within its crystal structure. A student heated a 12.10-gram sample of a
sveticcg [70]

Answer : The percent by mass of water the salt contain is, 55.3 %

Explanation : Given,

Mass of hydrated salt = 12.10 g

Mass of salt = 5.41 g

First we have to calculate the mass of water.

Mass of water = Mass of hydrate salt - Mass of salt

Mass of water = 12.10 g - 5.41 g

Mass of water = 6.69 g

Now we have to calculate the percent by mass of water the salt contain.

\text{Percent by mass of water}=\frac{\text{Mass of water}}{\text{Mass of hydrate salt}}\times 100

Now put all the given values in this expression, we get:

\text{Percent by mass of water}=\frac{6.69g}{12.10g}\times 100

\text{Percent by mass of water}=55.3\%

Therefore, the percent by mass of water the salt contain is, 55.3 %

5 0
3 years ago
The reaction of sodium peroxide and water produces sodium hydroxide and oxygen gas. The following balanced chemical equation rep
a_sh-v [17]

Answer:

3.925 mol.

Explanation:

  • From the balanced equation:

<em>2 Na₂O₂(s) + 2 H₂O(l) → 4 NaOH(s) + O₂(g) ,</em>

It is clear that 2 moles of Na₂O₂ react with 2 moles of H₂O to produce 4 moles of NaOH and 1 mole of O₂ .

<em>Using cross multiplication:</em>

4 moles of NaOH produced with → 1 mole of O₂ .

15.7 moles of NaOH produced with → ??? mole of O₂ .

<em>∴ The no. of moles of O₂ made =</em> (1 mole)(15.7 mole)/(4 mole) =  <em>3.925 mol.</em>

8 0
4 years ago
What is the molarity of a nitric acid solution if 43.13 mL 0.1000 M KOH solution is needed to neutralize 30.00 mL of the acid so
Leno4ka [110]

Answer:

0.144M

Explanation:

First, let us write a balanced equation for the reaction. This is illustrated below:

HNO3 + KOH —> KNO3 + H20

From the equation,

nA = 1

nB = 1

From the question given, we obtained the following:

Ma =?

Va = 30.00mL

Mb = 0.1000M

Vb = 43.13 mL

MaVa / MbVb = nA/nB

Ma x 30 / 0.1 x 43.13 = 1

Cross multiply to express in linear form

Ma x 30 = 0.1 x 43.13

Divide both side by 30

Ma = (0.1 x 43.13) /30 = 0.144M

The molarity of the nitric acid is 0.144M

8 0
3 years ago
"how many grams of sucrose (c12h22o11) are in 1.55 l of 0.758 m sucrose solution"
Ierofanga [76]
<span>You would use the equation: Molarity M equals amount of solution over volume of solution. So, 0.758 M equals x L divided by 1.55 L OR 0.758 M = x L / 1.55 L . To solve: 1.55 multiplied by 0.758 equals 1.1479. The answer is 1.1479.</span>
3 0
3 years ago
A scientist is observing a cell in notices the presence of starch what does this tell her about the cell
Harman [31]
The answer would be : 

 It is a plant cell because starch is the energy storing molecule in plant cells.

Hope this helps !

Photon
6 0
3 years ago
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