How much time would it take for 40000 atoms of sodium-24 (half-life is 15 days) to decay to 2500 atoms?

Answer:Charcoal will burn. You may also be able to distinguish it by smell, since it's rarely purged of all its “burnt wood” residue. Copper oxide will dissolve in a strong acid, such as hydrochloric or sulphuric and form a blue solution

Explanation:

Answer:

the reactants have more potential energy than the products have. The extra energy is released to the surroundings.

Answer:

O protein

Explanation:

Bee venom (BV) is a complex mixture of proteins and contains proteins such as phospholipase and melittin, which have an effect on blood clotting and blood clots.

HGD

The heat flows from inside to the outside direction because of lowering of temperature inside the thermos.

When a thermometer is suspended in an insulated thermos that contain a block of ice, the temperature recorded on the thermometer drops, the direction of heat flow is from inside to the outside the thermos. This is because of the insulating material in which the ice is kept and the lowering of the temperature.

So we can conclude that the heat flows from inside to the outside direction because of lowering of temperature inside the thermos.

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Answer:

propyne

Explanation:

Answer:

A grasping :)

Explanation:

The panda uses the "thumb" to grab onto bamboo to eat! Without this, the panda would not be able to eat the bamboo!

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Answer:

Thick layer of body fat for food storage and insulation

Explanation:

Polar bears store food for themselves and so do camels. Option B is not correct because bears do not definitely have small surface area and even if camels do they do not need to reduce heat loss because they stay in the deserts. For option C polar bears have thick fur and much body fat to protect itself from the cold. Lastly D cannot be true because camels don't normally have large feet they have small padded foot.

mass it the  amount of matter present in any object or body. Everything we see around us has mass. For example, a table, a chair, your bed, a football, a glass, and even air has mass.

The following redox reactions are classify as:

(a) 2H₂O₂ ⟶ 2H₂O + O₂: Disproportionation reaction (redox)

(b) Mg + 2AgNO₃ ⟶ Mg(NO₃)₂ + 2Ag: Single displacement reaction (redox)

(c) NH₄NO₂ ⟶ N₂ + 2H₂O: Decomposition reaction (redox)

(d) H₂ + Br₂ ⟶ 2HBr: Combination reaction (redox)

(a) 2H₂O₂ ⟶ 2H₂O + O₂

This reaction involves hydrogen peroxide (H₂O₂) breaking down into water (H₂O) and oxygen gas (O₂). The oxidation state of oxygen in hydrogen peroxide is -1, and in water, it is -2. Oxygen in oxygen gas has an oxidation state of 0. Therefore, oxygen is being reduced from -1 to 0. The oxidation state of hydrogen remains +1 in H₂O₂ and H₂O. Since one element (oxygen) is reduced and the other (hydrogen) remains unchanged, this is a disproportionation reaction (a type of redox reaction).

(b) Mg + 2AgNO₃ ⟶ Mg(NO₃)₂ + 2Ag

In this reaction, magnesium (Mg) reacts with silver nitrate (AgNO₃) to form magnesium nitrate (Mg(NO₃)₂) and silver (Ag). The oxidation state of magnesium changes from 0 to +2 in Mg(NO₃)₂, while the oxidation state of silver changes from +1 in AgNO₃ to 0 in Ag. This is a single displacement reaction (a type of redox reaction) because one element (magnesium) displaces another (silver) in the compound.

(c) NH₄NO₂ ⟶ N₂ + 2H₂O

This reaction involves ammonium nitrite (NH₄NO₂) decomposing into nitrogen gas (N₂) and water (H₂O). The oxidation state of nitrogen in NH₄NO₂ is +3, and in nitrogen gas (N₂), it is 0. The oxidation state of hydrogen changes from +1 in NH₄NO₂ to +1 in H₂O. Since nitrogen is being reduced from +3 to 0, and hydrogen remains unchanged, this is a decomposition redox reaction.

(d) H₂ + Br₂ ⟶ 2HBr

In this reaction, hydrogen gas (H₂) reacts with bromine gas (Br₂) to form hydrogen bromide (HBr). The oxidation state of hydrogen changes from 0 in H₂ to +1 in HBr, while the oxidation state of bromine changes from 0 in Br₂ to -1 in HBr. This is a combination reaction (a type of redox reaction) because two elements (hydrogen and bromine) combine to form a compound (hydrogen bromide), and their oxidation states change during the reaction.

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The solubility (in mol/L) of silver chromate in 1.20 M in potassium chromate,  silver nitrate and in pure water is

This is further explained below

Generally,The Chemical reaction is

Ag2CrO4 <----> 2 Ag+ + CrO42-

Ksp = [Ag+]^2[CrO42-]

1.12×10−12 = [Ag+]^2[CrO42-]

Hence

1.12×10−12.=(2X)^2*(1.2)

X = 5.0*10^-7 M

b)

1.12×10−12=(1.2)^2*(X)

1.12×10−12= 1.44 * 1(X)^1

X'' = 8.333*10^-13 M

In conclusion

1.12×10−12=(2X)^2*(s)

1.12×10−12= 4(X)^3

X'''= 6.694*10^-5 M

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Answer:

the size depends on where is moves across the periodic table.

Answer:

A. Seal them in a glass container in an atmosphere of argon (Ar) gas.

Because Argon is an inert/noble gas which do not react with other elements/radicals. Thus, best way to make two radicals/substance only react is to seal them in glass container consisting atmosphere of Argon (Ar)..

Note: I also dont know if it's correct answer.. Since I am just giving my logic.. I hope it will help you

- Regards Rishab...

Answer: C. Seal them in a glass container in an atmosphere of argon (Ar) gas.

Explanation: Founders Educere answer ;)

From the total pressure of the gaseous mixture, the partial pressure of xenon is 119.5 kPa

The partial pressure of a gas is the pressure that gas exerts when it is part of a mixture of gases which did not chemically react together.

The sum of the partial pressure of each gas in the mixture gives the total pressure.

In the gaseous mixtures above:

Total pressure = 248.8 kPa

Partial pressure of xenon = Total pressure - (Sum of partial pressure of the other gases)

Partial pressure of xenon = 248.8 - (77.3 + 52.0)

Partial pressure of xenon = 119.5

Therefore, the partial pressure of xenon is 119.5 kPa.

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Taking into account the reaction stoichiometry, 2.13 grams of magnesium was dissolved in the solution.

In first place, the balanced reaction is:

Mg²⁺(aq) + Na₂CO₃(aq) → MgCO₃(s) + 2 Na⁺(aq)

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

The following rule of three can be applied: If by reaction stoichiometry 1 mole of Na₂CO₃ react with 24.3 grams of magnesium, 0.0877 moles of Na₂CO₃ react with how much mass of magnesium?

[tex]mass of magnesium=\frac{0.0877 moles of Na_{2}C O_{3}x24.3 grams of magnesium }{1 mole of Na_{2}C O_{3}}[/tex]

mass of magnesium= 2.13 grams

Finally, 2.13 grams of magnesium was dissolved in the solution.

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Answer:

no.3 is your correct answer

Answer:

1. lava

2. caldera

3. true

4. true

5. before

Alkali metals require least amount of ionization energy.

Peaky Blinder fan? haha

Answer:

This isn't chemistry but the answer is Force = mass x acceleration

Answer:

Can you arrange it? I don't understand

Answer:

310.15 Kelvin. 98.6 Farenheit

Explanation:

To calcuate the celsius to Kelvin you add 273.15 to the celsius. To calculate the celsius to farenheit you do (°C × 9/5) + 32 = °F. For the example, (37°C × 9/5) + 32 = 98.6°F.

Answer:

130.159

Explanation:

P=0.987

V=66ml =66/1000=0.066 L

n/moles= ?

R=0.08206

T=86.9+273.15=360.5 K

Formula PV=RnT

n =PV/TR

n=(0.987 * 0.066)/(360.05 * 0.08206) = 0.002205

Now to obtain molar mass  you divide grams by mol.

0.287/0.002205 = 130.159

Answer:

0.93 M

Explanation:

Molarity = [tex]\frac{Moles}{Volume}[/tex]

4.0M = [tex]\frac{x}{0.007 L}[/tex]

4.0 M x 0.007 L = Moles = 0.028

Molarity = [tex]\frac{Moles}{Volume}[/tex]

Molarity = [tex]\frac{0.028 moles}{0.03 L}[/tex]

= 0.93 M

One mole of aluminum  contains 6.02 × 10²³ Al  particles. One mole of Al weighs 27 g. Hence 4.60 × 10²¹ Al particles or 0.007 moles weighs 0.208 g.  

One mole of a substance is its amount containing 6.02 × 10²³  atoms or molecules. This number is called Avogadro number. One mole of every elements contains Avogadro number of atoms.

Similarly one mole of every compound contains 6.02 × 10²³ molecules. The mass of one mole of compound is called its molar mass. Similarly mass of one mole of an element is called its atomic mass.

Al is 13th element in periodic table. Al is a metal.  One mole of Al contains 6.02 × 10²³ Al  atoms . Hence number of moles of   4.60 × 10²¹ Al particles is:

4.60 × 10²¹/ 6.02 × 10²³  = 0.0077 .

atomic mass of Al = 27 g/mol.

Then mass of 0.0077 moles =  0.0077 × 27 = 0.208 g

Therefore, the mass of  4.60 × 10²¹ Al particles is 0.208 g.

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Answer:

C. Technologies reduce the amount of carbon dioxide produced by

factories.

Explanation:

simply the answer is C. trust me, im very smart

Answer: it is coastline.

Explanation: This anwser would only makw sense because of the low elevation and the flat land.

The landform shared by Florida and the eastern border of South Carolina is the coastline. Option C is the correct answer.

Both states are located along the Atlantic Ocean and have a similar geographical feature characterized by flat land and low elevation along their eastern borders. Option C is the correct answer.

The coastline refers to the area where the land meets the sea. It is typically marked by sandy beaches, coastal marshes, and barrier islands. In the case of Florida and the eastern border of South Carolina, this coastline is known for its relatively flat terrain and low elevation, which makes it susceptible to flooding and storm surge during hurricanes. The coastline plays a significant role in the economies and ecosystems of both states. It attracts tourism and provides opportunities for recreational activities such as beachgoing, fishing, and boating. It is also a vital habitat for various marine and coastal species, including birds, turtles, and marine mammals.

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The complete question is, "Florida and the eastern border of South Carolina share a regional landform characterized by flat land and low elevation. Identify the landform shared by both states.

a. Karst

b. Keys

c. Coastline

d. Plateau"

Based on Hess law, the enthalpy change, ΔH of the reaction is +48.9 kJ.

The equation of the reaction of sulfur dioxide (SO2) and hydrogen disulfide (H2S) to produce sulfur and water is given below:

[tex]SO_2 + 2H_2S \rightarrow 3S + 2H_2O[/tex]

The ΔH of the reaction is calculated from the summation of the ΔH of the intermediate reactions according to Hess law.

SO2 (g) → S (s) + O2 (g) ΔH1 = +300.1 kJ

H2 (g) + S (s) → H2S (g) ΔH2 = –19.5 kJ

2H2 (g) + O2 (g) → 2H2O (g) ΔH3 = –290.1 kJ

ΔH of the reaction = ΔH1 + 2(-ΔH2) + ΔH3

ΔH of the reaction = 300 + 2 × -(-19.5) + (-290.1)

ΔH of the reaction = +48.9 kJ

Therefore, the ΔH of the reaction is +48.9 kJ.

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