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Answer:

Heat the water i'm pretty sure

Explanation:

Answer:

Option C. 24 days / 4 grams

Explanation:

From the question given above, the following data were obtained:

Days Elapsed >>>> Mass Remaining

0 >>>>>>>>>>>>>>> 16

12 >>>>>>>>>>>>>>> 11

24 >>>>>>>>>>>>>>> 8

36 >>>>>>>>>>>>>>> 6

A. Determination of the half-life of Thorium-234.

To determine the half-life, it is important to know the definition of half life.

Half-life is defined as the time taken for a substance to reduce to half its original mass.

From the table given above, we can see that the original mass of the isotope is 16 g (i.e at 0 day). By day 24, the mass of the isotope is 8 g (i.e half the original mass). Thus, the half-life of the isotope is 24 days.

B. Determination of the mass of the isotope remaining after 2 half lives.

Original amount (N₀) = 16 g

Number of half-lives (n) = 2

Amount remaining (N) =?

N = 1/2ⁿ × N₀

N = 1/2² × 16

N = 1/4 × 16

N = 4 g

Thus, 4 g of the isotope is remaining after 2 half lives.

Summay:

Half-life = 24 days

Amount remaining after 2 half-lives = 4 g

Option C gives the correct answer to the question.

Answer:

Soil erosion will increase because there are fewer plants to stabilize the soil.

Explanation:

study island

Answer:

0.02 kg

Explanation:

A P E X

The energy released by the decay process is  1.8 x 10¹⁵ J. Therefore the mass of the radioactive substance is 0.02 Kg.

Heavy unstable radioactive nuclei undergoes nuclear decay by the emission of charged particles to form more stable nuclei.

The relationship between energy and mass is given by Einstein's famous equation, E = mc², where E is the energy released in a process, m is the mass lost or gained in the process, and c is the speed of light.

To calculate the mass lost through radioactive decay, we need to rearrange this equation to solve for m:

m = E / c²

Plugging in the given energy released, E = 1.8 x 10^15 J, and the speed of light, c = 3 × 10⁸m/s, we get:

m = (1.8 x 10¹⁵ J) / ( 3 × 10⁸ m/s)²

m = 1.8 x 10¹⁵ J /9 x 10^16 m²/s²

m =0.02 kg

Therefore, the mass lost through radioactive decay is approximately 0.02 kg.

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Answer:

A

Explanation: The rubber around the wire is an insulator, and the wire i would imagine would be made out of something like copper.  Electricity runs through everything and without the insulator there, you'd be touching metal that electricity is running through.

Answer:

B. less than on the Earth

Explanation:

Weight is determined by gravity. Less gravity means less weight. The vehicle would weigh 501.3 pounds on Venus.

Answer:

B

Explanation:

Answer:

b . 0.351 L.

Explanation:

Hello!

In this case, since diluted solutions are prepared by adding an extra amount of diluent to a stock-concentrated solution, we infer that the number of moles of solute remains the same, therefore we can write:

[tex]C_1V_1=C_2V_2[/tex]

Thus, solving for the volume of the stock solution, V1, we obtain:

[tex]V_1=\frac{C_2V_2}{C_1}[/tex]

Now, by plugging in the given data we obtain:

[tex]V_1=\frac{1.2M*0.585L}{2.0M}\\\\V_1=0.351L[/tex]

Therefore, the answer is b . 0.351 L.

Best regards!

Answer:

the rate decreases and the curve increases

Explanation:

Answer: The mean of the normal curve is always in the center which is 100, so a standard deviation is a computed measure of how much scores vary around the mean score, meaning about 68% of the scores fall within one standard deviation of the mean, now 95% of the scores are going to fall within two standard deviations around the mean and with what you have left covers about 99.7% scores are within 3 standard deviations

Explanation:

Answer:the process of dissovlving makes the ecectrons in their atoms more closely bound

Explanation:

thats what my lesson said

The solution of water and salt are good conductor of electricity because the process of dissolving makes the electrons in their atoms free to move.

The correct option is (A).

Pure water and salt are bad conductor of electricity.

But the solution of water and salt is a good conductor because when a salt's dissociated it's ions are free to move about in solution when it dissolves, allowing a charge to flow freely.

Because it includes ions, the resulting solution will conduct electricity.

Thus, option (A) the process of dissolving makes the electrons in their atoms free to move, that's why the solution of water and salt are good conductor of electricity.

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Answer:

D. a new substance is formed.

Explanation: "Chemical reactions involve combining different substances. The chemical reaction produces a new substance with new and different physical and chemical properties. Matter is never destroyed or created in chemical reactions. The particles of one substance are rearranged to form a new substance." B. and C. are two different effects of chemical reaction, but not for all. Hope this helps ^-^.

Volume CO₂ produced  := 33.85 L

Given

120.0 grams of butane

55.0 liters of oxygen

Required

Carbon dioxide produced

Solution

Reaction(combustion of Butane) :

2 C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O.

mol of Butane (MW=58 g/mol) :

mol = mass : MW

mol = 120 : 58

mol = 2.069

At STP(1 atm, 273 K) , 1 mol gas=22.4 L, so for 55 L Oxygen :

mol O₂= 55 : 22.4 =2.455

Mol ratio of Butane and Oxygen = mol : reaction coefficient :

C₄H₁₀ : O₂ = 2.069/2 : 2.455/13 = 1.0345 : 0.189

Limiting reactant ⇒ O₂ (smaller ratio)

So mol CO₂ based on limiting reactant(O₂)

From equation, mol CO₂ : O₂ = 8 : 13, so mol CO₂ :

= 8/13 x mol O₂

= 8/13 x 2.455

= 1.511

Volume CO₂ at STP :

= 1.511 x 22.4 L

= 33.85 L

Answer: the bottom one is wave the one above is electromagnetic and the one above is transverse  

Explanation:

Answer

5.53moles

Explanation:

Given parameters

Number of molecules = 3.33 x 10²⁴

Unknown

Number of moles = ?

Solution

A mole of a substance contains the Avogadro's number of particles.

1 mole of a substance = 6.02 x 10²³

So, 3.33 x 10²⁴ molecules will contain;

3.33 x 10²⁴ / 6.02 x 10²³

= 5.53moles

Hey there!

Molar mass NaCl = 58.44 g/mol

58.44 g ----------------- 22.4 ( at STP )

3.2 g -------------------- Volume ??

Volume = ( 3.2 x 22.4 )  / 58.44

Volume = 71.68 / 58.44

Volume = 1.226 L

Hope this helps!

Answer:

V = 0.56 L

Explanation:

Given data:

Mass of NaCl = 3.2 g

Volume of chlorine gas = ?

Pressure and temperature = standard

Solution:

Chemical equation:

2NaCl    →     2Na + Cl₂

Number of moles of NaCl:

Number of moles = mass/molar mass

Number of moles = 3.2 g/ 58.44 g/mol

Number of moles = 0.05 mol

Now we will compare the moles of NaCl with chlorine;

              NaCl       :          Cl₂

                 2          :           1

                0.05      :       1/2×0.05 = 0.025 mol

Volume of chlorine:

PV = nRT

V = nRT/P

V = 0.025 mol × 0.0821 atm.L/mol.K × 273 K / 1 atm

V = 0.56 L

Answer:

The pressure increases by a factor of 1.27

Explanation:

From the question given above, the following data were obtained:

Initial temperature (T₁) = 100 °C

Final temperature (T₂) = 200 °C

Initial pressure (P₁) = P

Final pressure (P₂) =?

NOTE: The volume is constant.

Next, we shall convert celsius temperature to Kelvin temperature. This can be obtained as follow:

T(K) = T(°C) + 273

Initial temperature (T₁) = 100 °C

Initial temperature (T₁) = 100 °C + 273

Initial temperature (T₁) = 373 K

Final temperature (T₂) = 200 °C

Final temperature (T₂) = 200 °C + 273

Final temperature (T₂) = 473 K

Next, we shall determine the final pressure of the gas. This can be obtained as follow:

Initial temperature (T₁) = 373 K

Final temperature (T₂) = 473 K

Initial pressure (P₁) = P

Final pressure (P₂) =?

P₁ / T₁ = P₂ / T₂

P / 373 = P₂ / 473

Cross multiply

373 × P₂ = P × 473

Divide both side by 373

P₂ = P × 473 / 373

P₂ = 1.27 × P

Finally, we shall determine the factor by which the pressure of the gas increase as follow:

Initial pressure (P₁) = P

Final pressure (P₂) = 1.27 × P

From the above, we can see that the pressure increased by a factor of 1.27

The gas pressure would increase by a factor of 2.

At constant volume, the pressure of a gas increases with an increase in its temperature.

In this case, T1 = 100 and T2 = 200

            = 200/100

                  = 2

This means that the gas pressure would increase by a factor of 2 if the temperature were to be increased from 100 to 200 at constant volume.

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Answer:

high boiling aromatics

with the same ground glass joint.

Explanation:

The black connectors are more resistant to the reactant than the white connectors. This implies that the black connectors should be used when high boiling aromatics are present, Else, the tan connections can be used.

Thus, the connectors can combine different pieces of glassware or components with the same ground glass joint.

We have that for the Question  it can be said that the volume of water must be added to 250 mL of a 25% w/v stock solution of sodium chloride to prepare a 0.9% w/v sodium chloride solution is

x=444ml

From the question we are told

. H ow many milliliters of water must be added to 250 mL of a 25% w/v stock solution of sodium chloride to prepare a 0.9% w/v sodium chloride solution

Generally the equation for the volume of NaCl   is mathematically given as

[tex]V=\frac{25}{100}*250\\\\V=62.5ml[/tex]

Therefore

[tex]\frac{62.5}{250+x}*100=0.9\\\\x=6250-2250\\\\x=4000ml\\\\x=444ml[/tex]

Therefore

the volume of water must be added to 250 mL of a 25% w/v stock solu- tion of sodium chloride to prepare a 0.9% w/v sodium chloride solution is

x=444ml

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Answer:

18.4g

Explanation:

Given parameters:

Percentage composition:

49.47%  carbon

5.19% H

28.8% N

16.48% O

Mass of caffeine   = 37.1g

Unknown:

Mass of carbon  = ?

Solution:

To find the mass of the carbon:

  Mass of carbon = percentage composition of carbon x mass of caffeine

 Mass of carbon  = 49.47% x 37.1  = 18.4g

Answer:

167.980.

Explanation:

Hello!

In this case, since additions involving the display of the result with the appropriate number of significant figures involve the solution of the system without looking at them:

[tex]156.325 +11.65498 =167.97998[/tex]

Considering that 156.325 is significant to the thousandths and 11.65498 to the hundred thousandths, we infer that the result should be taken to the thousandths as well as 156.325; thus, we obtain:

[tex]167.980[/tex]

Because the second decimal nine is rounded to ten and therefore the 7 is taken to 8.

Best regards!

Answer:

1x10⁻⁶ is the Ka value for the acid

Explanation:

When a weak acid, HA, reacts with NaOH, some conjugate base, A⁻, is produced:

HA + NaOH → A⁻ + Na⁺ + H₂O

When HA is in excess, the NaOH added is equal to A⁻ produced and HA is Initial HA - NaOH added

After the reaction, the moles of HA are:

Initial moles HA: 2.00mmol

Moles NaOH: 0.020L * (0.050mol/L) = 1x10⁻³ moles = 1mmol

Moles HA: 2mmol - 1mmol = 1mmol

Moles A⁻ = Moles NaOH = 1mmol

Using H-H equation we can solve for pKa of the buffer:

pH = pKa + log [A⁻] / [HA]

Where [] could be taken as mmol of each species in the buffer:

6.00 = pKa + log 1mmol / 1mmol

6.00 = pKa

As pKa is -log Ka:

6.00 = -log Ka

10^-6 = Ka

Answer:

id say 4

Explanation:

hope this is right!

-Jules

Answer:

A Where warm, moist air masses traveling north collide with cool,

dry air masses traveling south

Answer:chlorophyll

Explanation:

The part of leaves that is responsible for absorbing sun's energy is chloroplast.

A chloroplast is an organelle found within the cells of plants and certain algae that is responsible for photosynthesis, which is the process by which solar energy is converted into chemical energy for growth.

Small organelles called chloroplasts are found inside plant cells and store sunlight energy.

The chloroplast's thylakoid membranes contain a light-absorbing pigment called chlorophyll, which is responsible for the plant's green color.

They are in charge of photosynthesis, which is the process of converting light energy into sugar and other organic molecules that plants and algae use as food.

They also produce amino acids and lipids, which are required for the production of chloroplast membranes.

Thus, the chloroplast is the part that traps the energy of the Sun.

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Answer:

should be A

Explanation:

Answer:

1 mole of any ideal gas occupies the same volume as one mole of any other ideal gas under the same conditions of temperature and pressure.So 1 L CO2 has same number of moles as 1 L O2 and 1 L N2 etc.This means that, assuming all the gases in air are ideal gases, if CO2 is 4.0 % by volume then it is also 4.0 % by moles, because a volume of each gas has the same number of moles.

Explanation: