Answer:
12.5%
Explanation:
Given data:
Volume/Volume % = ?
Volume of solute = 25 mL
Volume of solution = 200 mL
Solution:
Formula:
v/v% = ( volume of solute / volume of solution ) × 100
by putting values,
v/v% = ( 25 mL / 200 mL) × 100
v/v% = 0.125 × 100
v/v% = 12.5%
What part of the leaf is responsible for absorbing the sun’s energy?
Answer:chlorophyll
Explanation:
The part of leaves that is responsible for absorbing sun's energy is chloroplast.
What 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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Caffeine, a stimulant in coffee and some cola drinks, is 49.47% carbon, 5.19% H, 28.8% N, 16.48% O. What is the mass of carbon contained in 37.1 g of
caffeine?
a. 36.8 g
b. 1840 g
c. 24.39 g
d. 18.49 g
e.6.11 g
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
PLZ HELP 40 POINTS PLEASEEEEEE
Answer:
should be A
Explanation:
A planetary explorer vehicle on Earth weighs
557 pounds, what would it weigh on the
surface of Venus, which has 9/10 the gravity
of Earth?
A. more than on the Earth
B. less than on the Earth
C. the same as on Earth
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:
How many grams of sodium carbonate, Na2CO3, are needed to add to 0.125 kg of water to make a 0.200 m (molal) solution
Answer:
Mass = 2.65 g
Explanation:
Given data:
Mass of sodium carbonate = ?
Mass of water = 0.125 g
Molality = 0.200 m
Solution:
Formula:
Molality = number of moles of solute / mass of solvent in Kg
by putting values,
0.200 m = Number of moles of solute / 0.125 kg
Number of moles = 0.200 m × 0.125 kg
Number of moles = 0.025 mol
Mass of sodium carbonate:
Mass = number of moles × molar mass
Mass = 0.025 mol × 106 g/mol
Mass = 2.65 g
How would you separate salt & sand, taking into account the fact that salt is soluble in
water and sand is not?
A chemist has synthesized a monoprotic weak acid and wants to determine its Ka value. To do so, the chemist dissolves 2.00 mmol of the solid acid in 100.0 mL water and titrates the resulting solution with 0.0500 M NaOH. After 20.0 mL NaOH has been added, the pH is 6.00. What is the Ka value for the acid
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
1x10⁻⁶ is the Ka value for the acidIn a lab, you produce a quantity of the radioactive isotope thorium-234. Over the course of several weeks, the unstable isotope decays, and you measure the amount of thorium-234 remaining in the sample. You obtain the following data. What is the half life of Thorium-234? How much Thorium 234 will there be after two half lives?
Days Elapsed Grams of Thorium 234 Remaining
0 16
12 11
24 8
36 6
a. 36 days
b. 12 days
c. 24 days / 4 grams
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.
can you please help me with this question
Answer:
Heat the water i'm pretty sure
Explanation:
Microscale glassware kits include connectors to fit the smaller glassware. The black connectors should be used when _________ are present. Otherwise, the tan connectors can be used. The connectors can combine different pieces of glassware or components_______
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.
. H ow many milliliters 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
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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Analyze the normal curve of intelligence testing and explain the mean, standard deviation, and percentiles for the data.
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:
A person plugs a power cord into an electrical outlet in the wall. The power cord is covered in black rubber .Which statement is an accurate description of the materials?
Electrons would easily move through the person if there was no rubber around the wire
Electrons would not move through the wire if there was no rubber around the wire
Electrons easily move through the rubber around the wire
Electrons move through air when the cord is a few inches from the outlet
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.
If NaCl has a mass of 3.2g, what is the volume of chlorine gas at STP?
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
how much mass is lost through radioactive decay if 1.8 x 10^15 J are released?
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.
What is radioactive decay ?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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Helpp me plsssss!!!!!!!!!!!!!
Answer: the bottom one is wave the one above is electromagnetic and the one above is transverse
Explanation:
Cigarette lighters use butane, or C4H10, as their fuel. If 120.0 grams of butane burn with only 55.0 liters of oxygen gas at STP, how many liters of carbon dioxide are produced? Which reactant is your limiting reactant?
Volume CO₂ produced := 33.85 L
Further explanationGiven
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
Which statement best explains what will happen to the soil erosion in the area that was burned by the wildfire?
Answer:
Soil erosion will increase because there are fewer plants to stabilize the soil.
Explanation:
study island
How does a meteorologist use an understanding of what causes weather to predict a storm?
Perform the following
mathematical operation, and
report the answer to the
appropriate number of
significant figures.
11.65498 + 156.325 = [?]
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!
Neec help please :)
i don’t really know anything about this so i need help
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 ^-^.
Which example below is an example of deposition?
a. Water vapor in clouds changing to snow
b. Water vapor in clouds changing to rain
C. Liquid droplets forming on the outside of a cold can of soda
d. Ice cream dripping off your ice cream cone on a hot summer day
How much 2.0 M NH4NO3 is needed to make 0.585 L of 1.2 M NH4NO3 solution?
a
0.176 L
b
0.351 L
c
0.301 L
d
0.140 L
e
0.234 L
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!
the temperature of a rigid (i.e constant volume) sealed container of gas increases from 100 C to 200 C the gas pressure increases by a factor of
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.
Mathematically; P1/T1 = P2/T2 Where P1 = initial pressure, T1 = initial temperature, P2 = final pressure, and T2 = final temperature.In this case, T1 = 100 and T2 = 200
P2/P1 = T2/T1= 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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Which of these factors does not affect the climate?
1. Proximity to Water
2. Ocean Currents
3. Latitude
4. Puddles
5. Global Winds
6. Elevation
Answer:
id say 4
Explanation:
hope this is right!
-Jules
Pure water and pure salt are poor conductors of electricity. When salt is dissolved in water, the resulting solution conducts electricity well. Which statement explains why this occurs with these substances?
The process of dissolving makes the electrons in their atoms free to move
The process of dissolving makes the atoms in them free to move
The process of dissolving makes the electrons in their atoms more closely bound
The process of dissolving makes the atoms in them more closely bound to each other
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).
What makes a solution of water and salt a good conductor?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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Question 1 of 10
Where is a tomado most likely to form?
O A. Where warm, moist air masses traveling north collide with cool,
dry air masses traveling south
O B. On the northwestern side of a low-pressure system
C. Where a high-pressure system is lingering over an area
OD Over warm, tropical ocean water
SUBMIT
Answer:
A Where warm, moist air masses traveling north collide with cool,
dry air masses traveling south
The molar mass-of H2O is 18.02 gram /mol. How many moles are present in 3.33 x 1024 molecules of
H2O?
Select one:
a. 9.97 moles H20
b. 99.7 moles H2O
c. 2.00 x 1048 moles H20
d. 5.53 moles H20
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
Please answer this as soon as possible
