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cestrela7 [59]
3 years ago
9

The half-life of a strontium isotope is 25 years. How much of this particular isotope will remain after 100 years if the startin

g mass is 16 grams?
Chemistry
1 answer:
Phoenix [80]3 years ago
3 0

Answer:

1 gram

Explanation:

Half life = 25 years

Starting mass = 16 grams

Time = 100 years

Number of half lives = Time / Duration of Half life = 100 / 25 = 4

After first Half life;

Remaining mass = 16 / 2 =  8 g

After Second Half life;

Remaining mass = 8 / 2 =  4 g

After Third Half life;

Remaining mass = 4 / 2 =  2 g

After Fourth Half life;

Remaining mass = 2 / 2 = 1 g

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What is the exoeruent. Searched it up on google and only came up with two search results. None related to chemistry
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3 years ago
When heating a sample to extreme heat over a flame, you will often use a crucible. Before starting the heating, you should locat
Ghella [55]

Answer:

The equipments you should have ready to start the crucible experiment includes: safety goggles, crucible with lid, crucible tong, ring support with clay triangle, Bunsen burner and heat resistant tile.

Explanation:

Crucible is an equipment in the laboratory which is suitable for heating a sample to extreme heat over a flame, Modern laboratory crucible are made up of graphite- based composite materials for achievement of higher performance. Because extreme heat is involved, you should locate the correct labware for the experiment, including the equipment to safely handle and support the crucible. These equipments includes:

--> Safety goggles: Because you will work with chemical it is advisable to use a safety goggles which protects the eyes from dangerous floating chemical aerosol.

--> crucible with lid: This is the main apparatus with the lid (cover) which is used to cover the crucible to prevent spilling of the boiling chemical.

--> Crucible tong: These are scissors like tools used to grasp hot crucible.

--> Ring support with clay triangle: the clay triangle is used to hold crucible when they are being heated. They usually sit on a ring stand.

--> Bunsen burner: Produces a single open gas flame which can be used for heating.

With the safety equipments listed above, you can carry out experiment using the crucible. These equipments helps minimise laboratory hazard that may occur should Incase it's not available.

6 0
3 years ago
Base your answer on the diagram below and on your knowledge of Earth Science. The diagram represents a cutaway view of a flat-pl
algol13

Answer:

Explanation:

A solar collector is a device that absords Sun's heat energy to heat air or water. It is majorly used for heating purpose, and do not generate electricity directly.

The flow tubes and collector plate are black in color so as to increase the intensity of heat generated by the collector. A black body is a good absorber of heat, it absorbs most heat directed to the collector. Also, a black body is a good radiator of heat, the heat absorbed is rediated to the appropriate channels for the heating of water or air molecules. The black color increases the efficeincy and percentage of solar energy absorbed by the collector.

If a reflective color is used (e.g white), major percentage of the incident heat would be reflected. This would decrease the efficiency of the solar collector.

3 0
3 years ago
Suppose a 250. mL flask is filled with 0.30 mol of N_2 and 0.70 mol of NO. The following reaction becomes possible:N_2(g) +O2 →
Inessa [10]

Answer:

0.4 M

Explanation:

Equilibrium occurs when the velocity of the formation of the products is equal to the velocity of the formation of the reactants. It can be described by the equilibrium constant, which is the multiplication of the concentration of the products elevated by their coefficients divided by the multiplication of the concentration of the reactants elevated by their coefficients. So, let's do an equilibrium chart for the reaction.

Because there's no O₂ in the beginning, the NO will decompose:

N₂(g) + O₂(g) ⇄ 2NO(g)

0.30 0 0.70 Initial

+x +x -2x Reacts (the stoichiometry is 1:1:2)

0.30+x x 0.70-2x Equilibrium

The equilibrium concentrations are the number of moles divided by the volume (0.250 L):

[N₂] = (0.30 + x)/0.250

[O₂] = x/0.25

[NO] = (0.70 - 2x)/0.250

K = [NO]²/([N₂]*[O₂])

K = \frac{(\frac{0.70 -2x}{0.250})^2 }{\frac{0.30+x}{0.250}*\frac{x}{0.250} }

7.70 = (0.70-2x)²/[(0.30+x)*x]

7.70 = (0.49 - 2.80x + 4x²)/(0.30x + x²)

4x² - 2.80x + 0.49 = 2.31x + 7.70x²

3.7x² + 5.11x - 0.49 = 0

Solving in a graphical calculator (or by Bhaskara's equation), x>0 and x<0.70

x = 0.09 mol

Thus,

[O₂] = 0.09/0.250 = 0.36 M ≅ 0.4 M

3 0
3 years ago
Which of the following list all the elements that are present in a molecule of potassium carbonate K2C03?
meriva
H
Since K stands for potassium, C stands for Carbon and O stands for Oxygen
3 0
3 years ago
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