Answer:
4.3 %
Explanation:
Trust me.
1. Marie left her briefcase at home and had to return to get it. At which point did she turn back around to go home?
Answer:
She turned back at the point at which she forgot she left her briefcase. If this isn't the correct answer, please be more specific in the question.
Explanation:
The equation above is not balanced. Balance the equation on a scratch sheet of paper. Match each letter to the correct coefficient that will balance the equation. Remember, if there is no coefficient, it is understood to be 1. Some numbers may be used more than once.
In order to balance the equation, A would be 1, B would be 3, C would be 1, and D would be 2 respectively.
Balancing chemical equationA balanced chemical equation has the same number of each of the component atoms at the reactant and product sides.
Thus, the balanced chemical equation for the reaction in the illustration would be:
[tex]CS_2 + 3O_2 --- > CO_2 + 2SO_2[/tex]
Thus:
A = 1B = 3C = 1D = 2More on balancing chemical equations can be found here: https://brainly.com/question/15052184
How much concentrated 12M hydrochloric acid is needed to prepare 100. mL of a 2.0M solution?
Taking into account the definition of dilution, 16.67 mL of 12 M hydrochloric acid is needed to prepare 100. mL of a 2.0M solution.
Definition of dilutionWhen it is desired to prepare a less concentrated solution from a more concentrated one, it is called dilution.
Dilution is the process of reducing the concentration of solute in solution, which is accomplished by simply adding more solvent to the solution at the same amount of solute.
In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.
A dilution is mathematically expressed as:
Ci×Vi = Cf×Vf
where
Ci: initial concentration.Vi: initial volume.Cf: final concentration.Vf: final volume.Volume of hydrochloric acid neededIn this case, you know:
Ci= 12 M Vi= ?Cf= 2 MVf= 100 mLReplacing in the definition of dilution:
12 M× Vi = 2 M× 100 mL
Solving:
Vi = (2 M× 100 mL)÷ 12 M
Vi= 16.67 mL
In summary, 16.67 mL of 12 M hydrochloric acid is needed to prepare 100. mL of a 2.0M solution.
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Breathing is one of the most universal and habitual practices that humans do. Most of the time, we don't even think about it. Our lungs allow us to breathe in air and provide much needed oxygen to the rest of the body. It also eliminates carbon dioxide to get rid of this waste material of our body. This breathing process is made possible because of Boyle's law.
In at most 100- word essay, explain how Boyle's law applies to human breathing apparatus and suggest ways on how to take good care of our healthy lungs.
Answer:
lets Do it dude
We can breathe air in and out of our lungs because of Boyle’s law. According to Boyle’s law, if a given amount of gas has a constant temperature, increasing its volume decreases its pressure, and vice-versa.When you inhale, muscles increase the size of your thoracic (chest) cavity and expand your lungs. This increases their volume, so pressure inside the lungs decreases. As a result, outside air rushes into the lungs. That’s because a gas always flows from an area of higher to lower pressure.When you exhale, muscles decrease the size of your chest cavity and squeeze your lungs. This decreases their volume, so pressure inside the lungs increases. As a result, air rushes out of the lungs, flowing from an area of higher to lower pressure.Explanation:
Checkmate
How many liters of nitrogen gas are needed if 15.9g of aluminum is produced?
please show work
Answer:
6.6 L ( if you wrote your Q correctly)
Explanation:
2 Al + 1 N2 = 2 Al N
Al mole weight = 26.981 gm
given 15.9 Al How many L of N2 are needed?
15.9 / 26.981 = .5893 moles of Al
we need 1/2 as many moles of N2 ( from the balanced equation above)
= .29465 moles of N2
22.4 L/ mole for STP gas = 6.6 L
If the Ksp of NaCl is experimentally determined to be 53.9, then what is the concentration of Na (in M) when it begins to crystallize out of solution
For the concentration of Na in M when it begins to crystallize out of the solution is mathematically given as
Na+ = 0.125M
what is the concentration of Na in M when it begins to crystallize out of the solution?Generally, the equation for the Ksp of the solution is mathematically given as
Na⁺+CL⁻
Ksp = SxS
53.9 = s^2
S = 7.34
Molar mass Nacl 58,44
Solubility = 7.34/58.44
Solubility = 0.125M
In conclusion, the concentration of Na in M when it begins to crystallize out of the solution
Na+ = 0.125M
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Citric acid is made by oranges. When citric acid dissolved in water , it produces a relatively small number of hydronium ions. Citric is best described as a
Answer:
Citric acid is a weak organic acid found in citrus fruits.
Explanation:
Which of the following scenarios best describes separation by distillation?
A sample of ocean water is boiled in a glass flask. A solid remains in the flask, and a hot gas flows
into a cooling chamber. When the as cools enough, it condenses back into a liquid in a separate flask.
O a stip of paper with a sample of ink is placed in a jar. The liquid runs up the paper, resulting in
colored bars running up in a line.
O A funnel and porous paper are used to separate solids in a sample of dirty water from the liquid.
O Aliquid sample is spun quickly in a centrifuge. A layer of solid forms on the bottom of the test tube
over time.
What mass of water will be needed to change its temperature 25°C using 4,532 J of heat
energy?
The mass of the water that will be needed to change its temperature by 25°C is : 43.33 grams
Given data :
Energy = 4532 J
Change in temperature = 25°C
Cw = 4.184 J/gk
Determine the mass of water needed
We will apply the formula below
Q = mCwΔt ---- (1 )
4532 = m * 4.184 * 25
therefore :
m = 4532 / 104.6
= 43.33 grams
Hence we can conclude that the mass of water needed to change the temperature by 25°C is 43.33 grams
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A 16.0 g sample of methane gas, CH4, the gas used in a chemistry lab, has a volume of 5.0 L at 27ºC. Calculate the pressure.
Answer:
4.9 atm
Explanation:
convert 16.0g of CH4 to moles
16.0 g CH4 x 1 mol CH4/16.0 g CH4 = 1.00 mol of methane
convert the temp into Kelvins: 27 + 273 = 300.K
PV = nRT
(P) (5.0 L) = (1.00 mol) (0.0821 L atm/mol K) (300.K)
P = 4.9 atm
Marie had to wait at the railroad tracks from a train to pass. How long did she wait?
Answer:
she waited 30 minutes
Explanation:
i need brain liest
Of the following elements, which has the lowest electronegativity?
Br
Cl
Ca
Mg
A stock solution has a concentration of 1.5 M SO2 and is diluted to a 0.54 M solution with a volume of 0.18 L. What was the volume of the stock solution
The volume of the stock solution that has a concentration of 1.5 M SO2 and is diluted to a 0.54 M solution with a volume of 0.18 L is 0.065L.
How to calculate volume?The concentration of a solution can be calculated using the following formula:
C1V1 = C2V2
Where;
C1 = initial concentration = 1.5MC2 = final concentration = 0.54MV1 = initial volume = ?V2 = final volume = 0.18L1.5 × V1 = 0.54 × 0.18
1.5V1 = 0.0972
V1 = 0.0972 ÷ 1.5
V1 = 0.065L
Therefore, the volume of the stock solution that has a concentration of 1.5 M SO2 and is diluted to a 0.54 M solution with a volume of 0.18 L is 0.065L.
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The instantaneous rate data in Table 3 were obtained for
the reaction H2(g) + 2NO(g) →H2O(g) + N2O(g) at a
given temperature and concentration of NO. How does
the instantaneous rate of this reaction change as the
initial concentration of Hy is changed? Based on the
data, is [Hz] part of the rate law? Explain.
Answer:
A) As the initial concentration of H₂ is increased, the reaction rate also increases.
B) Yes, [H₂] is part of the rate law.
Explanation:
For the reaction:
[tex]\displaystyle \text{H$_2$}_\text{(g)} + 2\text{NO}_\text{(g)} \longrightarrow \text{H$_2$O}_\tex{(g)} + \text{N$_2$O}_\text{(g)}[/tex]
The rate law will have the form:
[tex]\displaystyle \text{Rate} = k\left[\text{H$_2$}\right]^n\left[\text{NO}\right]^m[/tex]
Where n and m are the respective order of reactions.
From the table, we can see that as the concentration of H₂ increases, the instantaneous rate also increases.
Therefore, [H₂] is indeed part of the rate law. If it isn't, changing its concentration will have no effect on the instantaneous rate of the reaction.
The average resting heart rate is between
A. 80-90 bpm
B. 90-100 bpm
C. 60-70 bpm
D. 70-75 bpm
The average resting heart rate is between is 70- 75 bytes per minute. This include systolic pressure and diastolic pressure. Hence, option D is correct.
What is heart rate?The count of heart beats per unit time is called heart rate. For a normal condition at the resting time the average heart rate is 70 -75 beats per minute.
The heat beats we hear is the impulse from the open and closing of the heart valves. This includes the systolic and diastolic blood pressures. For a normal person at the systolic rate is 120 mm Hg and diastolic rate is 80 mm Hg.
The blood pressure rate is depends on the diet, inheritance and other factors such as age, physical activities, mental situations etc. For a normal person, the average resting heart rate is 70 - 75 bpm.
To find more on heart rate, refer here:
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how can you separate sand and water without filter paper
Answer:
through Decantation
Explanation:
Decantation: Decantation is pouring out of upper clear layer of liquid into another container to separate two immiscible liquids or to separate different substances in a suspension mixture.
Therefore, we could use decantation once the sand particles settle down by gently pouring the water into another container. Once the water is transfered, we'll be left with sand in the bottom of the first container.
Hope that helps...
Write a net ionic equation for the reaction that occurs when excess hydroiodic acid and nickel(II) sulfide are combined.
Explanation:
Step 1: Write the balanced "molecular" equation:
[tex]2HI(aq) + NIS (s) → NiI₂(aq) + H₂S(g)[/tex]
Step 2: H₂S is written in molecular form. Consult the solubility and net ionic equation rules on the information page to determine which of the other substances will dissociate:
[tex]2HI(aq) + NIS (s) → NiI₂(aq) + H₂S(g)[/tex]
yes no yes
Step 3: Dissociate all soluble salts, strong acids, and strong bases (except calcium hydroxide). Leave together all "not soluble" salts and weak acids or bases:
[tex] {2H₃O}^{ + } (aq) + {2I}^{ - } (aq) + NiS(s)→ { Ni}^{2 + }(aq) + {2I}^{ - }(aq) + H₂S(g) + 2H₂O(l)[/tex]
Step 4: Cross out "spectator ions" that appear on both sides of the reaction (these ions do not participate in the chemistry) and rewrite the "net" reaction using the smallest possible coefficients:
[tex] {2H₃O}^{ + } (aq) + NiS(s) → { Ni}^{2 + } (aq) + H₂S(g) + 2H₂O(l)[/tex]
Below is the thermochemical equation for the combustion of octane.
How much heat is released during the combustion of 8 moles of octane (C8H18)
Question 4 options:
Impossible to answer this question with the information provided.
43,764 kilo joules of heat is released
7,004,224 kilo joules of heat is released
2735 kilo joules of heat is released
87,528 kilo joules of heat is released
from equation 2 moles = - 10,941 kJ
for 8 moles:
8/2 x -10,941 = -43,764 kJ
-43,764 kJ heat is released during the combustion of 8 moles of octane.
How to find the amount of heat released?To calculate the amount of heat released in a chemical reaction, use the equation Q = mc ΔT, where Q is the heat energy transferred (in joules), m is the mass of the liquid being heated (in kilograms), c is the specific heat capacity of the liquid (joule per kilogram degrees Celsius), and ΔT is the change in temperature.
from equation 2 moles = - 10,941 kJ
for 8 moles:
8/2 x -10,941 = -43,764 kJ
When octane is burned, carbon dioxide gas is generated, as shown in the reaction equation. This is typical of hydrocarbon combustion reactions, such as octane and propane.
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What is the mass of 89.6 L of NH3(g) at STP?
Please help I don’t understand!
Answer:
68g
Explanation:
GMM of NH^3=14+3=17g
Mass =mole×GMM=4×17=68g
hope this helps<33 :)
The cell membrane is a flexible structure that surrounds both plant and animal cells. The arrangement of molecules within the cell membrane makes it semi-permeable. That is, the cell membrane allows some substances to easily diffuse into and out of the cell, but it prevents the diffusion of other substances.
Plant and animal cell diagram
The cell wall is a rigid structure that surrounds plant cells. The materials found in the cell wall protect the plant cells and give plants structural support.
Which conclusion can be made given the above information?
Answer:
The true answer is the Cell membrane and animal cells invisible
Explanation: nothing. eshh
Which molecule has a trigonal planar shape?
Answer:
Structure of boron trifluoride, an example of a molecule with trigonal planar geometry.
Explanation:
Name five renewable energy resources.
Answer:
Solar energy, geothermal energy. Wind energy. Hydropower, Biomass.
Explanation:
HELP ME OUT PLS!!!!!!
During which lunar phase would you observe the highest tides?
A) Phase 1
B) Phase 2
C) Phase 3
D) Phase 4
Answer:
3
Explanation:
This is the answer because when it is full moon the tides are higher.
what is the volume occupied by 6.8gm of H2S at STP (at mass H=1,S=32)
The volume occupied by 17g of H2S at s.t.p. is [H = 1.00, S = 32.0, Molar volume = 22.4 dm3]
Options
A) 11.2dm 3
A 1 kg block of iron sits outside in the direct sun from 8am to 10am. At 8am the temperature of the block was 20.0°C and at 10am the temperature of the block was 27.5°C.
How much heat did the block of Iron absorb from the sun?
use q=mcΔT
Answer:
About 3.5 kJ.
Explanation:
Recall the heat transfer equation:
[tex]\displaystyle q = mC\Delta T[/tex]
Where q is the heat; m is the mass of the substance; C is its specific heat; and ΔT is the change in temperature.
The given specific heat of iron is 462 J/kg -°C.
Substitute and evaluate. Ensure correct units:
[tex]\displaystyle \begin{aligned} q & = (1\text{ kg})\left(\frac{462\text{ J}}{\text{kg -$^\circ$C}}\right)(27.5\text{ $^\circ$C} - 20.0\text{ $^\circ$C}) \\ \\ & = (1\text{ kg})\left(\frac{462\text{ J}}{\text{kg -$^\circ$C}}\right)(7.5\text{ $^\circ$C}) \\ \\ & = 3.5\times 10^3 \text{ J} = 3.5\text{ kJ}\end{aligned}[/tex]
Therefore, the block of iron absorbed about 3.5 kJ of heat.
So
Q=mc∆TQ=1(462)(7.5)Q=3500JThe block absorbed 3500J of heat
pH of a 4.5x10-6 M solution of HCl.
[tex]\text{pH} = -\log[H^{+}] = - \log[4,5 \times 10^{-6}] = 5.34[/tex]
Which statement is an example of competition?
"I'll win everyone at the camp games this year."
Explanation:
This above statement is an example of competition because it signifies a matter anticipating an upper hand towards some other matter.
A balloon has a volume of 12.0 L at a pressure of 98.7. kPa. What will be the new volume when the pressure drops to 56.7 kPa?
Answer:
20.89 LITERS
Explanation:
P1V1=P2V2
P1V1 / P2 = V2
98.7 * 12/56.7 = 20.89 LITERS
**Multiple Choice**
**Q:** When an acid reacts with a metal, what is one of the usual products?
(a) carbon dioxide
(b) water
(c) hydrogen gas (this?)
(d) salt
(e) none of the above
Answer:
When an acid reacts with a metal, what is one of the usual products?
C) Hydrogen gas
Explanation:
How many grams of glucose are disolved in 500 ml of a .50% glucose solution
Answer:
To make 500 ml, you need 5x this amount. 5 x 4.33 g = 17.21 g glucose in a final volume of 500 ml
Explanation:
hope this helps