Answer:
The correct answer is - C. 0.500 mg.
Explanation:
In this case, the half-life of the iodine-131 is 8 days and the initial amount is given 4 mg. According to this after every 8 days, half of the initial value of the iodine-131 remains only.
8 days or 1st half-life = A(i)* 1/2
16 days or two half-life = A(i)* 1/4
24 days or three half-life = A(i)* 1/8
and the remaining amount A would be
= A(i)*1/2^n
= 4 * 1/2^3
= 4 *1/8
= 0.500 mg
3. How is the equilibrium position of this reaction affected
by the following changes?
2802 (g) + O2 (g) <-------------→ 2 S03(g) + heat
a. Lowering the temperature.
b. Decreasing the pressure
c. Removing oxygen
d. Adding sulfur trioxide (SO3).
Answer:
Explanation: a) Reaction is exothermic because heat is released
If temperature is lowered, amount of products is increased,
equilibrium transfers to right
b) If pressure decreases, equilibrium transfers to direction in which amount of gas moles is greater, also in left (reactants)
c) If Oxygen is removed, reaction which produces more oxygen is favoured, also balance changes to reactansts (left)
d) Adding product causes equilibrium transfer to left (reactansts)
A dead tree is not an important part of an ecosystem. T or F
how does a flourmill work?
Explanation:
Answer ⬇️
These mills employed millstones that rotated against one another to crush grains into flour mill machine. They rely on a process of crushing grain between two rapidly rotating rollers, then separating the ground grain into individual components, including bran, germ and endosperm.
➡️dhruv73143(⌐■-■)
how many grams are in 3.0 moles of H2O
Answer:
18x3=54 gram
Explanation:
When you express molecular mass (in case of molecule)/atomic mass(in case of atom) in gram it will be equivalent to one mole. For example:
12 gram Carbon atom = 1 mole of Carbon atom = N number of Carbon atom
16 gram Oxygen atom= 1 mole of Oxygen atom = N number of Oxygen atom
32 gram Oxygen molecule (O2) = 1 mole of Oxygen molecule (O2) = N number of Oxygen molecule (O2)
similarly 1 mole of water is equivalent to molecular mass of water x 3 that is 18x3=54 gram. It would constitute 3N molecules of water.
N: Avogadro's number : 6.022140857 × 10^23
Is this an alpha or beta decay?
Answer:
alpha decay
Explanation:
The pressure of a sample of helium in a 200. ml container is 2.0 atm. If the helium is compressed to a pressure of 40. atm without changing the temperature, what would be the new volume of the gas
Answer:
[tex]V_2=10mL[/tex]
Explanation:
Hello there!
In this case, according to the given information, it will be possible for us to solve this problem by using the Boyle's law as an inversely proportional relationship between pressure and volume:
[tex]P_2V_2=P_1V_1[/tex]
In such a way, we solve for the final volume, V2, and plug in the initial volume and pressure and final pressure to obtain:
[tex]V_2=\frac{P_1V_1}{P_2} \\\\V_2=\frac{2.0atm*200.mL}{40.atm}\\\\V_2=10mL[/tex]
Regards!
List and describe two differences between pure substances and mixtures. Check all that apply. Check all that apply. The composition of a pure substance depends on the source, but the composition of a mixture doesn't depend on the source. The composition of a pure substance is always the same, regardless of the source, but the composition of a mixture can vary. The state of a pure substance is always the same, but the state of a mixture can vary. Mixtures can be separated into their components only by chemical changes; some pure substances can be separated into components by physical change. Mixtures can be separated into their components by physical changes; some pure substances can be separated into components by chemical change.
Answer:
The composition of a pure substance is always the same, regardless of the source, but the composition of a mixture can vary.
Mixtures can be separated into their components by physical changes; some pure substances can be separated into components by chemical change.
Explanation:
A chemically pure substance has a well defined and constant composition. The composition of a chemically pure substance remains the same irrespective of its source. Also, the components of a chemically pure substance may be separated by chemical changes.
Mixtures have a variable composition depending on their respective sources. The composition of a mixture varies with the source of the mixture and mixtures are separated by physical processes.
ONLY ANSWER IF YOU ARE SURE PLEASE
2Cr^3 + 3Zn(s) -> 2Cr(s) + 3Zn^2 + (aq) which reactant is reduced and which is oxidicided
Answer:
Cr is oxidised
and
Zn is reduced
[ Reduced reactant ] :
Cr^( + 3 ) + 3 e^( - 1 ) ===》 Cr^( 0 )
_____________________________
[ Oxidicided reactant ] :
Zn^(0) ===》Zn^( + 2 ) + 2 e^( - 1 )
Which will decrease the rate of a reaction?
changing the temperature from 90ºC to 40ºC
adjusting the concentration from 30 ng to 60 ng
placing the substance in a smaller container
grinding the substance into a powder
Explanation:
The reaction rate decreases with a decrease in temperature. Catalysts can lower the activation energy and increase the reaction rate without being consumed in the reaction. Differences in the inherent structures of reactants can lead to differences in reaction rates.
Calculate the number of atoms in 6.5 moles of NaCI
Answer:
[tex]1 \: mole = 6.02 \times {10}^{23} \: atoms \\ 6.5 \: moles = (6.5 \times {6.02 \times 10}^{23} ) \: atoms \\ = 3.913 \times {10}^{24} \: atoms[/tex]
The concentration of carbon-14 in a piece of wood from an ancient burial mound indicates that two half-lives of this radioisotope have passed. If the half-life (t 1/2) for carbon-14 is 5730 years, approximately how many years ago did this sample of wood die?
If the half-life for carbon-14 is 5730 years, then it will take 11,460 years to complete die of this sample.
What is half life period?Half life period is a time of decay in which concentration of reactant is left half of its initial concentration, means half of the reactant will convert into product.
Total time of decay will be calculated as:
T = (t)ⁿ, where
t = half life time = 5730 years
n = number of half lives = 2 (given)
On putting values, we get
T = (5730)² = 11,460 years
Hence required time for decay is 11,460 years.
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Answer:
The first part is 5 and the second part is 28,650
A gas has a pressure of 3.33 kPa at 343 K. What will the new pressure be at 655 K if the volume does not change?
Phenolphthalein meaning
Answer:
Phenolphthalein is a chemical compound with the formula C20H14O4 and is often written as "HIn" or "phph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.
Answer:
Phenolphthalein is a chemical compound, a colorless crystalline solid, though pink in a alkaline solution, and is also used as an acid-base indicator.
Explanation:
The volume of gas in a balloon is 1.90L at 21.0°C.The balloon is heated, causing it to expand to a volume of 5.70L. what is the new temperature of the gas inside the balloon?
Answer: The new temperature is [tex]63^{o}C[/tex].
Explanation:
Given: [tex]V_{1}[/tex] = 1.90 L, [tex]T_{1} = 21.0^{o}C[/tex]
[tex]V_{2}[/tex] = 5.70 L, [tex]T_{2} = ?\\[/tex]
Formula used to calculate new temperature is as follows.
[tex]\frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}[/tex]
Substitute the values into above formula as follows.
[tex]\frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}\\\frac{1.90 L}{21.0^{o}C} = \frac{5.70 L}{T_{2}}\\T_{2} = 63^{o}C[/tex]
Thus, we can conclude that the new temperature is [tex]63^{o}C[/tex].
where do fossils live
answer questions 3 and 4 for a brainly!
Answer:
The correct answer is -
3. Butyne
4. Pentene
Explanation:
The names of such organic compounds are classified on the number of the carbon atoms and based on a number these prefixes are attached -
Meth - one carbon
Eth - two carbons
Prop - three carbons
But - four carbons
Pent - five carbons, and so on
The bonds can be identified by names of an organic compound by their suffixes -
- ane = single bond
- ene = double bond
-yne = triple bond
Thus, for question 3, carbon numbers are 4 and triple bond so Butyne, and similarly for question 4, 5 carbon atoms and double bond so Pentene.
Which does not affect global wind belts
A.) air pressure
B.) land breezes
C.) the Coriolis effect
D.) the sun
Answer:
D. The Sun
Explanation:
The Sun does not affect global wind belts.
Land breeze does not affect global wind belts whereas other factors such as air pressure, Coriolis effect and the sun affected global wind patterns.
Factors affecting global wind beltsUnequal heating of the Earth's surface forms large global wind patterns. Those area which are near the equator, the sun warm air and this warm air rises at the equator and moves toward the poles. At the poles, the cooler air sinks and moves back toward the equator.
So we can conclude that land breeze does not affect but sun creates affect on the global wind pattern.
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URGENT! PLEASE HELP ASAP
A sample of Argon gas at a pressure of 813 mm Hg and a temperature of 54°C, occupies a volume of 10.4 liters. If the gas is heated at a constant pressure to a temperature of 74°C, the volume of the gas sample will be _____ L?
explain how lithium atom is positive charge
what are the environmental impacts of coal
Answer:
Look down below
Explanation:
Environmmetal impacts that coal can cause is Sulfur dioxide (SO2), which contributes to acid rain and respiratory illness.
AND.....
Nitrogen oxides (NOx), which contribute to smog and respiratory illnesses. Particulates, which contribute to smog, haze, and respiratory illnesses and lung disease
How many grams are in 3.14 moles of PI₃?
Answer:
[tex]\boxed {\boxed {\sf 1290 \ g \ PI_3}}[/tex]
Explanation:
We want to convert from moles to grams, so we must use the molar mass.
1. Molar MassThe molar mass is the mass of 1 mole of a substance. It is the same as the atomic masses on the Periodic Table, but the units are grams per mole (g/mol) instead of atomic mass units (amu).
We are given the compound PI₃ or phosphorus triiodide. Look up the molar masses of the individual elements.
Phosphorus (P): 30.973762 g/molIodine (I): 126.9045 g/molNote that there is a subscript of 3 after the I in the formula. This means there are 3 moles of iodine in 1 mole of the compound PI₃. We should multiply iodine's molar mass by 3, then add phosphorus's molar mass.
I₃: 126.9045 * 3=380.7135 g/mol PI₃: 30.973762 + 380.7135 = 411.687262 g/mol 2. Convert Moles to GramsUse the molar mass as a ratio.
[tex]\frac {411.687262 \ g \ PI_3}{ 1 \ mol \ PI_3}[/tex]
We want to convert 3.14 moles to grams, so we multiply by that value.
[tex]3.14 \ mol \ PI_3 *\frac {411.687262 \ g \ PI_3}{ 1 \ mol \ PI_3}[/tex]
The units of moles of PI₃ cancel.
[tex]3.14 *\frac {411.687262 \ g \ PI_3}{ 1 }[/tex]
[tex]1292.698 \ g\ PI_3[/tex]
3. RoundThe original measurement of moles has 3 significant figures, so our answer must have the same. For the number we calculated, that is the tens place.
1292.698The 2 in the ones place tells us to leave the 9.
[tex]1290 \ g \ PI_3[/tex]
3.14 moles of phosphorous triiodide is approximately equal to 1290 grams of phosphorus triodide.
Two hundred liters of helium at 2.00 atm and 28.0 °C is placed into a tank with an internal pressure of 5.92 atm. Find the volume of the helium
after it is creleased into the tank when the temperature of the tank.remains 28.0°C.
liters (Round to three sig figs)
Answer:
27*6 dkfkdh hshsnnsbssshs ss. hhshsns svs s ssjssgsyz
Explanation:
ysgshssbs
5.(08.02 MC)
A 0.0400 M NaCl solution was formed when 32.0 grams of NaCl was dissolved in enough water. What was the total volume of the solution formed? (5 points)
O 7.20 liters
9.80 liters
13.7 liters
18.1 liters
Answer:
13.7 liters
Explanation:
I took the test and got it right
The total volume of the NaCl solution whose molarity is 0.04 M is 13.7 liters.
What is molarity?Molarity of any solution is define as the number of moles of solute present in per liter of the solution and it will be represented as:
M = n/V
Mass from moles will be calculated as:
n = W/M, where
W = given mass of NaCl = 32g
M = molar mass of NaCl = 58.44g/mol
mole = 32g / 58.44g/mol = 0.547 mol
Molarity of solution = 0.04 M
On putting values on the above equation, we get volume as:
V = 0.547 mol / 0.04mol/L
V = 13.67 L = 13.7L
Hence required value of volume is 13.7 L.
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how many grams of caco3 are needed to react with 15.2g of hcl
Answer:
Balanced equation:
CaCO3 (s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
1mol CaCO3 will react with 2 mol HCl
Mol HCl in 32.8mL of 1.25M solution = 32.8mL / 1000mL/L * 1.25mol /L = 0.041 mol HCl
This will react with 0.041/2 = 0.0205 mol CaCO3
Molar mass CaCO3 = 100g/mol
Mass of CaCO3 reacted = 0.0205mol *100g/mol = 2.05g CaCO3.
Grams are the unit of weight or mass that depicts the quantity of a substance. The mass of calcium carbonate reacted is 2.05 gm.
What is mass?Mass is the product of the moles of the compound and its molar mass, it is given in grams.
The balanced chemical reaction is given as:
[tex]\rm CaCO_{3} (s) + 2HCl(aq) \rightarrow CaCl_{2}(aq) + CO_{2}(g) + H_{2}O(l)[/tex]
From the reaction, 1 mole of calcium carbonate reacts with 2 moles of hydrochloric acid.
Moles of hydrochloric acid is calculated as:
[tex]\begin{aligned} \rm n &= \rm Molarity \times Volume (L)\\\\&= 0.0328 \times 1.25\\\\&= 0.041\;\rm mol\end{aligned}[/tex]
Now, the moles of calcium carbonate it will react with will be 0.0205 moles.
Mass of calcium carbonate is calculated as:
[tex]\begin{aligned} \rm mass &= \rm molar\; mass \times moles\\\\&= 0.0205 \times 100\\\\&= 2.05 \; \rm g\end{aligned}[/tex]
Therefore, 2.05 gm of calcium carbonate is needed to react with 15.2 gm of hydrochloric acid.
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Consider the balanced reaction
below:
2Na + 2H2O → 2NaOH + H2
How many moles of sodium
hydroxide (NaOH) will be produced
from the complete reaction of 15.0 g
sodium?
Answer:
Moles of sodium = 15.0⋅g22.99⋅g⋅mol−1 = 0.652⋅mol . Given the stoichiometry of the reaction, clearly 0.652⋅mol sodium hydroxide will result.
Explanation:
please mark me
From the balanced chemical equation of the reaction, it is clear that, 2 moles or 46 g of sodium metal produce 2 moles of NaOH. Then, 15 g or 0.65 moles of Na metal will give 0.65 moles or 26 g of NaOH.
What is a balanced reaction ?The balanced chemical equation of a reaction represent the correct stoichiometry of all the reactants and products in the reaction. It is balanced as per the law of conservation of masses. Hence, the total mass of the reactant side is equal to the total mass of the product side.
From the given balanced chemical equation of the reaction, it is clear that, 2 moles of Na reacts with one mole of water to give two moles of NaOH and one mole of hydrogen gas.
Atomic mass of Na = 23 g/mol
no.of moles in 15 g = 15 g /23g/mol = 0.65 moles.
2 moles of Na gives 2 moles of NaOH. Then, 0.65 moles of Na will given 0.65 moles of NaOH.
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21. What type of cells are found on the retina and provide signals to the brain about incoming light?
A photoreceivers
B optic cells
C photoreceptors
D retina cells
Answer:
Explanation:
have a good day
If 250. ML of water are poured into the measuring cup, the volume reading is 8.45 oz . This indicates that 250. ML and 8.45 oz are equivalent. How many milliliters are in a fluid ounce based on this data?
Answer:
[tex]1oz=29.589ml[/tex]
Explanation:
From the question we are told that:
Initial Volume [tex]v_1=250ml[/tex]
Final Volume [tex]v_2=8.45oz[/tex]
Generally the equation for one ounce is mathematically given by
[tex]1oz=\frac{v_1}{v_2}[/tex]
Therefore
[tex]1oz=\frac{250}{8.45}[/tex]
[tex]1oz=29.589ml[/tex]
Which of the following single replacement reactions will take place?
O Al + Mg(NO3)2 -->
O Cu + Mg(NO3)2 -->
Ca + Mg(NO3)2 -->
O Zn + Mg(NO3)2
-->
Answer:
O Al + Mg(NO3)2 -->
Explanation:
plz help me solve this question is it A,B,C or D
Answer:
B - To increase the rate of the reaction
Explanation:
Catalysts speed up the reaction without being reactants or products, so aren't used up in the reaction.