Answer:
[Sr(OH)₂] = 0.699 M in Sr(OH)₂ sol'n (1 sig. fig)
Explanation:
Concentrated-1 Sr(OH)₂ = M₁ = unknown Concentration-2 HCl = M₂ = 0.350M
Volume of Concentrate = V₁ = 15ml Volume of Diluted = V₂ = 29.8ml
Using the Dilution Equation
Molarity x Volume of Concnt'd Soln = Molarity x Volume of Diluted Soln
From definition of molarity (M) = moles solute / volume of solution in Liters
=> moles solute = Molarity x Volume in liters*
*Note: if volume units are the same on both sides of the dilution equation then one may retain the volume in ml.
M₁ x V₁ = M₂ x V₂
=> 15ml · [Sr(OH)₂] = 30ml X 0.350M HCl soln
=> [Sr(OH)₂] = 29.8ml X 0.350M / 15ml = 0.695333... (calculator answer)
=> [Sr(OH)₂] = 0.7 M in Sr(OH)₂ sol'n (1 sig. fig)
__________________________________
work check:
M₁ x V₁ = M₂ x V₂
0.6953M x 15ml = 0.35M x 29.8ml
10.43 moles = 10.43 moles QED
A sample of helium gas is heated from 20.0°C to 40.0°C. This
heating process causes the gas to expand to a volume of 585
mL. What was the original volume of the helium gas?
a 292mL
b 370mL
C 548mL
d 625mL
Answer:
C. 548mL
Explanation:
Attached is an image of the explanation. Hope this helps!
Combined gas law states that "the ratio of the product of pressure and volume and the absolute temperature of a gas is equal to a constant".
Temperature ,T₁ = 20⁰C = 20+273.15K = 293.15K
Temperature, T₂ = 40⁰C = 40+273.15K = 313.15K
According to combined gas law,
P₁V₁/n₁T₁ = P₂V₂/n₂T₂
Where, n is moles of substance
P is pressure
P and n are considered to be a constant.
Thus, V₁/T₁ = V₂/T₂
V₁ = V₂T₁/T₂
V₁ = ?,
V₂ = 585mL = 585mL x 293.15K/313.15K
V₁ = 548mL
Hence, the original volume of the helium gas is 548mL.
What is pressure?"Pressure is the force of all the gas particle/wall collisions divided by the area of the wall."
What is volume?"Volume is the amount of space occupied by a substance."
What is temperature?"Temperature is the measure of hotness or coldness expressed in terms of any of several scales, including Fahrenheit and Celsius."
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which is expected to have a higher boiling point? why? CH3CH2OH or CH3CH2NH2
Answer:
Explanation: Ethanol, CH3CH2OH, has the highest of the three boiling points because it has the strongest dipole–dipole forces between molecules due to hydrogen bonding. ... Dimethyl ether, CH3OCH3, has the second- highest boiling point because it has dipole–dipole forces between molecules.
Which of the following best describes careers that use chemistry?
A. Careers that involve scientific research or chemistry instruction
B. Only careers that involve scientific research
C. Only careers that involve chemical manufacturing
D. A variety of careers in many different industries
Answer:
D
Explanation:
True or False: Having more moles of solute definitely means a higher concentration (molarity) solution
Answer:
True
Explanation:
The statement having more moles of solute definitely means a higher concentration (molarity) solution is true.
What is Molarity?Molarity is used to define concentration of any solution and it will be define as the no. of moles of solute present in per liter of solution and it is represented as:
M = n/V
From the equation it is clear that molarity of is directly proportional to the moles of the solute present in that. So, more no. of moles shows more concentration of solution.
Hence, given statement is true.
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How many grams of hydrogen gas are needed to completely react with excess nitrogen to produce 26.7 grams of ammonia (NH3)? N2 + H2 → NH3
Answer:
4.74 g H2
Explanation:
First, balance your reaction:
N2 + 3H2 --> 2NH3
Now convert 26.7 g NH3 to moles NH3 by dividing by its molar mass (17.031 g/mol). Then multiply by the mole ratio of 3 mol H2 for every 2 mol NH3 to get moles of H2. Finally multiply by the molar mass of H2 (2.016 g/mol) to get grams of H2.
26.7 g NH3 • (1 mol NH3 / 17.031 g NH3) • (3 mol H2 / 2 mol NH3) • (2.016 g H2 / 1 mol H2) = 4.74 g H2
What is the partial pressure of helium gas in a mixture that contains 8.00 grams of helium and 8.60 mol argon gas with a total pressure of 48.0 torr?
Multiple Choice
9.06 torr
15.2 torr
23.1 torr
38.9 torr
Answer:
[tex]P_{He}=9.06torr[/tex]
Explanation:
Hello there!
In this case, we can identify the solution to this problem via the Dalton's rule because the partial pressure of helium is given by:
[tex]P_{He}=x_{He}P_T[/tex]
Whereas the mole fraction of helium is calculated by firstly obtaining the moles and then the mole fraction:
[tex]n_{He}=8.00g\frac{1mol}{4.00g}=2.00mol\\\\ x_{He}=\frac{n_{He}}{n_{He}+n_{Ar}} \\\\ x_{He}=\frac{2.00mol}{2.00mol+8.60mol}\\\\x_{He}=0.189[/tex]
Then, we calculate the partial pressure as shown below:
[tex]P_{He}=0.189 *48.0torr\\\\P_{He}=9.06torr[/tex]
Best regards!
What volume of 0.215 M HCl is required to neutralize 50.0 mL of
0.800 M NaOH?
Answer:
186 mL HCl
Explanation:
M1V1 = M2V2
M1 = 0.215 M HCl
V1 = ?
M2 = 0.800 M NaOH
V2 = 50.0 mL
Solve for V1 --> V1 = M2V2/M1
V1 = (0.800 M)(50.0 mL) / (0.215 M) = 186 mL HCl
How many moles can be found in 1.5 x 10^24 atoms of Calcium?
A simple bread recipe calls for 400 g of flour,
7 g of salt (NaCl), 1 g of yeast, and 0.3 L of water (H2O). You have
exactly 0.6 mol of salt. If you want to use all of the salt, how many
loaves of bread could you make? How much of each of the other
ingredients would you need? PLEASE HELP !!
Answer:
5 loaves of bread you could make.
5g yeast, 1.5L water, 2000g of flour
Explanation:
To solve this question, we must, as first, convert the moles of salt to grams (1mol NaCl = 58.44g/mol -Molar mass-). With this mass we can find the amount of breads we can use and the amount of the other ingredients:
Mass NaCl:
0.6mol * (58.44g / mol) = 35g salt
Loaves of bread:
35g salt * (1 loave / 7g NaCl) = 5 loaves of bread you could make
Other ingredients:
1g yeast * 5 = 5g yeast
0.3L H2= * 5 = 1.5L H2O
400g flour * 5 = 2000g flour
The number of 5 loaves of bread you could make.
And, 5g yeast, 1.5L water, 2000g of flour
Calculation of the number of loaves, yeast, water, and flour:
Here we determine the following calculations:
For Mass NaCl:
0.6mol * (58.44g / mol) = 35g salt
Now
Loaves of bread:
= 35g salt * (1 loave / 7g NaCl)
= 5 loaves of bread you could make
And,
Other ingredients:
1g yeast * 5 = 5g yeast
0.3L H2= * 5 = 1.5L H2O
400g flour * 5 = 2000g flour
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what are possible source of error for rusting of a nail
Answer:
A nail can rust when exposed to oxygen. the molecules of iron on the surface of the nail exchange atoms with the oxygen in the air and produce a new substance, the reddish brown ferrous oxide i.e rust.
what is a chemical property
Answer:
Chemical property is a characteristic of a particular substance that can be observed in a chemical reaction.
Explanation:
Hope this helps :)
Answer:
A chemical property is any of a material's propertiesthat becomes evident during, or after, a chemicalreaction; that is, any quality that can be established only by changing a substance's chemical identity. ... They can also be useful to identify an unknown substance or to separate or purify it from other substances.
Which countries have an Taiga (Boreal Forest) biome? (Hint: You may have to click the globe to find out.)
Click this link: https://thewildclassroom.com/biomes/boreal-forests/
Question 1 options:
Canada
Finland
Sweden
Norway
Russia
Answer:
I think it is Greenland and Canada
Explanation:
The Taiga or boreal forest are present in the inland Canada, and Russia.
What are Taiga or boreal forests?Taiga is coniferous forest, pines, spruce, and fur are common trees of this forest.
They are present in cold regions, and are adapted to survive in cold areas.
Different types of animals live in this forest, who are adapted to live in cold area, such as birds, rodents, bears, deer, moose, etc.
Siberian tiger is a native species of taiga forest, it is the world's largest cat.
Thus, the correct option is A, Canada, and E, Russia.
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By which method the following mixture can be separated?(i)mixture of colours (ii) Minerals oil.
Answer:
mixture of colours answer
What is the product of 2.3 x 1014 and 5.4 x 10-3?
A. 1.4 x 1011
B. 2.8 x 1016
C. 4.3 x 1010
D. 1.2 x 1012
Answer:
c.
Explanation:
I think???
A student added copper wire to a flask containing silver nitrate after a period of three hours,the flask and its contents looked like this Did a chemical reaction occur? Use evidence and scientific reasoning to support your claim
Answer:
Yes
Explanation:
Cause the student add wire To the flash and changed colour
Answer: Yes
Explanation: Because the color changed and one of the ways to see if a chemical reaction occured is color change.
Calculate E∘cell for the following balanced redox reaction:
2Cu(s)+Ca2+(aq)→2Cu+(aq)+Ca(s)
The standard cell potential of this reaction is obtained from the calculations as 3.21 V
What is an electrochemical cell?An electrochemicall cell is onee in which electrical energy is produced from a chemical reaction. A cell reaction is sponteanous of the standard cell potential is positive.
Now;
E∘cell = E∘cathode - E∘anode
E∘cathode = 0.34 V
E∘anode = (-2.87 V)
E∘cell = 0.34 V - (-2.87 V) = 3.21 V
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Need help ASAP, Which kind of reactions have higher activation energies?
Group of answer choices
endothermic reactions
exothermic reactions
synthesis reactions
Answer:
endothermic reactions
Explanation:
Endothermic reactions are those reactions that absorbs heat from the surroundings as opposed to the exothermic reaction that releases heat energy. This heat absorption that characterizes endothermic reactions causes the surrounding to be cool.
However, in an endothermic reaction, more energy is needed to be absorbed in order to break the bonds of the reactants to form products, hence, making the activation energy of endothermic reactions HIGHER.
How many moles of H 3 PO 4 are produced when 20.0 g of HCI are produced by the reaction PCl 5 +4H 2 O H 3 PO 4 +5HCl ?
Answer:
Approximately [tex]0.110\; \rm mol[/tex].
Explanation:
Balanced equation for this reaction:
[tex]\rm PCl_5 + 4\; H_2O \to H_3PO_4 + 5\, HCl[/tex].
Look up the relative atomic mass of [tex]\rm H[/tex] and [tex]\rm Cl[/tex] on a modern periodic table:
[tex]\rm H[/tex]: [tex]1.008[/tex].[tex]\rm Cl[/tex]: [tex]35.45[/tex].Calculate the molar mass of [tex]\rm HCl[/tex]:
[tex]\begin{aligned}&M({\rm HCl}) \\ &= (1.008 + 35.45)\; \rm g \cdot mol^{-1} \\ &\approx 36.46\; \rm g \cdot mol^{-1}\end{aligned}[/tex].
Calculate the number of moles of molecules in that [tex]20.0\; \rm g[/tex] of [tex]\rm HCl[/tex]:
[tex]\begin{aligned}n &= \frac{m}{M} \\ &\approx \frac{20.0\; \rm g}{36.46\; \rm g \cdot mol^{-1}} \approx 0.549\; \rm mol\end{aligned}[/tex].
In the balanced reaction, the coefficient of [tex]\rm H_3PO_4[/tex] and [tex]\rm HCl[/tex] are [tex]1[/tex] and [tex]5[/tex], respectively. The ratio between these two coefficients is:
[tex]\displaystyle \frac{n({\rm H_3PO_4})}{n({\rm HCl})} = \frac{1}{5}[/tex].
In other words, this reaction would produce five times as many [tex]\rm HCl[/tex] molecules as [tex]\rm H_3PO_4[/tex] molecules.
Calculation shows that in this question, approximately [tex]0.549\; \rm mol[/tex] of [tex]\rm HCl[/tex] molecules were produced. Calculate the number of moles of [tex]\rm H_3PO_4[/tex] molecules that were produced:
[tex]\begin{aligned}& n({\rm H_3PO_4}) \\ &= n({\rm HCl}) \cdot \frac{n({\rm H_3PO_4})}{n({\rm HCl})} \\ & \approx 0.549\; \rm mol \times \frac{1}{5} \approx 0.110\; \rm mol\end{aligned}[/tex].
What must remain constant if Charles' law is to be applied to a
given sample of a gas?
a Pressure
b Volume
C Temperature
d None of the above
Answer:
pressure must remain constant
Explanation:
charles law= V/T
where pressure remains constant
If Charles' law is to be applied to a given sample of a gas, then it must have constant pressure.
What is gas law?Gas law are the hypothesis which tells about the behavior of gas at different conditions.
According to the Charles' Law, volume of the gas at any constant pressure and no. of moles of gas is directly proportional to the temperature of the gas at that condition. Charles' law is represented as:
V ∝ T, where
V = volume of gas
T = temperature of gas
Hence option (a) is correct i.e. pressure.
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4. Automotive airbags inflate when sodium azide, NaN 3, rapidly decomposes to its constituent elements according to the chemical equation, 2 NaN3 → 2 Na + 3 N2. 2 Na + 3 N2. How many moles of nitrogen are produced when 10000. milligrams of sodium azide decomposes? 0.07691142 mone a. 3.0000 moles 357 2 b. 0.15385 moles c. 0.23077 moles d. 230.77 moles
Answer:
B or 0.1538
Explanation:
Remark
For every mol of NaN3 that decomposes, 3 mols of N2 are produced.
10000 mg = 10 grams
NaN3 = 23 + 3*14
NaN3 = 23 + 42
NaN3 = 65
So set up the following proportion
10 grams / 65 = x /1 Cross multiply
10 * 1 = 65 x Divide by 65
x = 10 / 65
x = 0.1538 moles which is B I think
Which solute generally creates aqueous solutions with lower freezing points? Explain why this substance has a greater effect on the freezing point.
pls help! ^^
Answer:
The freezing point depression can be calculated using the pure solvent freezing point and the molality of the solution.
At the freezing point, the vapor pressure of both the solid and liquid form of a compound must be equal.
The freezing point of a substance is the temperature at which the solid and liquid forms are in equilibrium.
To reattain equilibrium, the freezing point of the solute and solvent mixture is lowered relative to the original pure solvent.
How many half lives will have passed if 7500 atoms of carbon-14 remain? How old would the rock be? (Pls explain, I'm very confused)
Answer:
the answer is B hsjsjjsksks
what causes fraud in public centres
Answer:
there are three causes of fraud, namely, perceived pressure, perceive opportunities and rationalizations. Pressure can take many forms, including financial and employment pressure. A fraudster also may commit fraud when there is an opportunity, frequently related to weak internal control.
Explanation:
This study found that the most popular type of fraud is misappropriation of assets, including theft of cash and inventories. No significant differences were seen in terms of fraudster position, as they can come from both the lower and the executive level. However, the majority of the fraudsters come from the operational and sales department. This study also found that majority of the fraudsters in the case study were male, new employees and young adults. Their motivations to commit fraud include lack of understanding about fraud behaviour, opportunity to commit fraud and lifestyle and financial pressure.
(hope this helps can i plz have brainlist :D hehe)
Can somebody please answer this for me
4NH3+6NO --> 5N2 + 6H20
When a student runs this reaction in their chemistry lab, they notice that they run out SO quickly and some NH3 is left in the container. Which reactant is the limiting reactant?
N2
NH3
NO
water
Answer:
NO
Explanation:
4 NH₃ + 6 NO → 5N₂ + 6H₂OWater and N₂ cannot be the answer because they are products of the reaction, not reactants.
The fact that some ammonia (NH₃) is left in the container once the reaction is finished tells us that NH₃ is the reactant in excess.
The remaining reactant is thus the limiting reactant. The correct answer is NO.
Identify the quantum numbers for the electron gained when an F2 ion becomes an F3 ion
Answer: n= 3, l= 0 , m= 0 and s=[/tex]\frac{-1}{2}[/tex]
Explanation:
Principle Quantum Numbers : It describes the size of the orbital and the energy level. It is represented by n. Where, n = 1,2,3,4....
Azimuthal Quantum Number : It describes the shape of the orbital. It is represented as 'l'. The value of l ranges from 0 to (n-1). For l = 0,1,2,3... the orbitals are s, p, d, f...
Magnetic quantum number : It describes the orientation of the orbital. It is represented as 'm'. The value of m ranges from -l to +l.
Spin quantum number: It describes the spin of the electron. It is represented as 's'. The value of s can be +1/2 or -1/2
[tex]F^{2-}:11: 1s^22s^22p^63s^1[/tex]
[tex]F^{3-}:12:1s^22s^22p^63s^2[/tex]
Thus electron enters 3s orbital , thus n= 3, l= 0 , m= 0 and s=[/tex]\frac{-1}{2}[/tex]
Equation: 2Mg + O2 = 2MgO
If neither reactant is limiting and the reaction goes to completion, the mass of the product should be equal to...
a) the molar mass of the product
b) the sum of the mass of the reactants
c) the mass of oxygen gas
d) the mass of magnesium
4. The soap-water-oil mixture that you made in your amphipathic home lab exercise may be best
described as:
a) an amphipathic substance
b) a hydrophilic substance
c) a hydrophobic
substance
d) an emulsion
Explanation is in a file
bit.[tex]^{}[/tex]ly/3a8Nt8n
Why does the cake and pan feel different to your hand when you take them out of the oven? Explain
Answer:
bcs the oven heated it up?
Explanation:
Which best describes what happens during a typical energy conversion?
A. Some energy is destroyed.
B. Some energy is created.
C. The total amount of all forms of energy stays the same.
D. Some mass changes into energy, and some energy changes into
mass.
The best answer for your question would be C. The total amount of all forms of energy stays the same.
First, let's eliminate the wrong choices. According to the Law of Conservation of Energy, you cannot create nor destroy energy, so you can eliminate choices A and B.
Also according to the Law of Conservation of Energy, the total amount of energy will always be the same. It may transform into different forms of energy.
To me, D doesn't sound very correct. For this one you can take an aducational guess, but I do not believe it would be D.
Hope this helps; have a great day!
Nitric acid and nitrogen monoxide react to form nitrogen dioxide and water, like this: (aq)(g)(g)(l) At a certain temperature, a chemist finds that a reaction vessel containing a mixture of nitric acid, nitrogen monoxide, nitrogen dioxide, and water at equilibrium has the following composition: compoundamount Calculate the value of the equilibrium constant for this reaction. Round your answer to significant digits.
Answer:
The reaction given is
Chemistry homework question answer, step 1, image 1
Since in equilibrium constant expression, the concentration of liquid components is not written.
Hence the equilibrium constant expression for the above reaction can be written as
Chemistry homework question answer, step 1, image 2
where [NO] = equilibrium concentration of NO
[NO2 ] = equilibrium concentration of NO2
[HNO3 ] = equilibrium concentration of HNO3
Step 2
Given : mass of NO at equilibrium = 18.6 g
mass of NO2 at equilibrium = 15.1 g
and mass of HNO3 at equilibrium = 13.1 g
Since molar mass of HNO3 = 63 g/mol, molar mass of NO = 30 g/mol and molar mass of NO2 = 46 g/mol
Hence the moles of gases at equilibrium are
Chemistry homework question answer, step 2, image 1
Step 3
Since mass of solution = mass of HNO3 + mass of water = 13.1 + 234.8 = 247.9 g
Assuming density of solution = density of water = 1.00 g/mL
=> mass of solution = volume of solution X density of solution
=> 247.9 = 1.00 X volume of solution
=> volume of solution = 247.9 mL = 0.2479 L
Explanation: