Answer:
volume = 15
density = 10
Explanation:
mass = 150 grams
volume = 45 - 20 = 15
density = mass / volume
density = 150 / 15 = 10
define what is halflife
Answer: the time taken for the radioactivity of a specified isotope to fall to half its original value.
Explanation:
Answer:
Half-life is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo, or how long stable atoms survive, radioactive decay.
Using standard reduction potentials from the ALEKS Data tab, calculate the standard reaction free energy for the following redox reaction. Round your answer to significant digits. N2H4 + 4OH + 2Cl2
Answer:
-973 KJ
Explanation:
The balanced reaction equation is;
N2H4(aq) + 2Cl2(g) + 4OH^-(aq)---------> 4Cl-(aq) + 4H ^+(aq) + 4OH^-(aq) + N2(g)
Reduction potential of hydrazine = -1.16 V
Reduction potential of chlorine = 1.36 V
From;
E°cell= E°cathode - E°anode
E°cell= 1.36 - (-1.16)
E°cell= 2.52 V
∆G°=- nFE°cell
n= number of moles of electrons = 4
F= Faraday's constant = 96500 C
E°cell = 2.52 V
∆G°=- (4 × 96500 × 2.52)
∆G°= -972720 J
∆G°= -972.72 KJ
Write the volume of the liquid, in milliliters, using the proper number of significant figures.Express your answer with the appropriate units.
Answer:
19.5 mL
Explanation:
The change that happen the piece of paper during the burning process?
Answer: Chemical
Explanation:
When paper is burned, it creates a chemical change.
Answer:
Explanation:
Hey, there!!
The answer is chemical change.
When the paper is burned it changes into an ash. Which is a chemical change. { as it can't be reversed }.
Hope it helps...
Which of the following statements is not true for an exothermic reaction?a. The temp. of the surroundings increasesb. The temp of the reaction systems increasesc. The products have a higher heat content than the reactantsd. Heat passes from the reaction system to the surroundingse. The enthalpy change for the reaction is negative
Answer:
The products have a higher heat content than the reactants
Explanation:
Recall that the change in enthalpy for a reaction is obtained from
∆Hreaction= enthalpy of products - enthalpy of reactants
For an exothermic reaction, enthalpy of reactants > enthalpy of products, hence ∆Hreaction is negative.
This implies that the heat content of reactants is greater than that of products for an exothermic reaction. Hence the option selected in the answer is false as written.
nder what reaction conditions does the electrophilic chlorination of aromatic compounds usually occur
Answer:
Cl2/FeCl3
Explanation:
The electrophilic chlorination of aromatic compounds proceeds in the presence of Cl2/FeCl3.
The function of the Lewis acid FeCl3 is to 'activate' the chlorine molecule towards electrophilic substitution. This occurs by the formation of a 'chlorine cation' which attacks the aromatic ring followed by deprotonation of the aromatic ring to retain the aromaticity of the compound.
How many significant figures are in the quantity 12.0 mL?
O A. 1
B. 2
C. 3
O D. 12
Answer:
C. 3
Explanation:
12.0 - 3 significant figures 1,2 and 0, because 0 is after decimal point.
A statement that can be proven by observation or measurement is known as a(n):
a.
opinion
b.
value
c.
fact
d.
belief
Please select the best answer from the choices provided
A
B
C
D
The correct answer for this question is that a statement that can be proven by observation or measurement is known as a fact. The other possible answers here simply refer to idea that different individuals can place value on, but that are not necessarily known to be true.
What is the wavelength, in nanometers, of light with a frequency of 5.89 x 10¹⁴ s⁻¹?
Answer:
≅ 50, 909 nm
Explanation:
Wavelength, λ = [tex]\frac{speed}{freq}[/tex]
Given:
speed of light = [tex]3*10^{8} m/s[/tex]
f = 5.89 × [tex]10^{14}[/tex]
∴ λ = 3×[tex]10^{8}[/tex] / 5.89 × [tex]10^{14}[/tex]
= 0.0000509 m ≅ 50, 909 nm
Let me know if you need further assistance
if a mixture of 90 g of hydrogen sulfide and 70.5 g of chromium oxide are allowed to raeact what mass of water can be formed
Answer:
24.84 g
Explanation:
The balanced reaction equation is;
Cr2O3(s) + 3H2S(g) ⟶Cr2S3(s) + 3H2O(l)
We must first determine the limiting reactant
For chromium III oxide;
Amount of chromium III oxide = mass/molar mass = 70.5g/ 151.99 g/mol = 0.46 moles
If 1 mole of chromium III oxide yields 3 moles of water
0.46 moles of chromium III oxide yields 0.46 × 3 = 1.38 moles of water
For hydrogen sulphide
Amount of hydrogen sulphide = mass/molar mass = 90g/ 34 gmol-1 = 2.64 moles
If 3 moles of H2S yields 3 moles of water
2.64 moles of H2S yields 2.64 × 3/3 = 2.64 moles of water
Hence chromium III oxide is the limiting reactant.
Mass of water produced= 1.38 moles × 18gmol-1= 24.84 g
Suppose you obtain 0.500 g of a compound after synthesis with the following solubility: In ethanol 4.24g/100 mL at 78 ⁰C and 0.30g/100 mL at 0 ⁰C. Performing recrystallization to purify the compound using 10 mL of ethanol, what would you expect the theoretical yield from the experiment to be? Show your calculations. (6 points)
Answer:
0.394g
Explanation:
At 78°C, you can dissolve, in 10mL of ethanol, 0.424g of the compound will dissolve. Then, you must filter the solution.
You take the filtrate of the solution in ethanol and cool it to 0°C. Om mL, only 0.03g of the compound will remain in solution. The other part is the purified compound.
Its mass (Theoretical yield) is:
0.424g - 0.030g =
0.394gidentify balance chemical equation from the following
C+O2=CO2
H2+O2=H2O
2PbO+C=Pb+CO2
Fe2O3+2Al=Al2CO3+2Fe
Answer:
C+O2=CO2
Explanation:
no.of atoms on reactant side= no.of atoms on product side
A reagent bottle contains a stock solution of 0.90% by mass of sodium chloride, NaCl.
The density of the solution is 1.00 g cm ?. Calculate
(i) the mole fraction of NaCl
(ii) the molality of NaCl solution
(111) the volume of the stock solution required to prepare 100 mL of 0.01 M NaCl
solution.
Answer:
I. 2.79x10⁻³
II. 0.155m
III. 6.49mL of the solution you must add from the stock solution
Explanation:
A solution of 0.90% by mass NaCl means that, in 100g of solution, you have 0.90g of NaCl. In other words, there are 0.90g of NaCl + 99.1g of water.
I. Mole fraction of NaCl is the ratio between moles of NaCl and total moles of solution.
Moles NaCl:
0.90g * (1mol / 58.44g) = 0.0154 moles NaCl
Moles water:
99.1g water * (1mol / 18.01g) = 5.50 moles water.
Total moles = 5.50 +0.0154 moles = 5.518 moles
Mole fraction NaCl: 0.0154 / 5.518 moles =
2.79x10⁻³II. Molality is the ratio between moles of solute (NaCl) and kg of solvent.
There are 99.1g of water = 0.0991kg.
Molality is: 0.0154 moles / 0.0991kg
0.155mII. 100mL of a 0.01M are:
100mL = 0.100L * (0.01 mol / L) = 1x10⁻³ moles of NaCl
In 100g = 100mL (Density of 1g/mL) there are 0.0154 moles. To have 1x10⁻³ moles you need:
1x10⁻³ moles of NaCl * (100mL / 0.0154 moles) =
6.49mL of the solution you must add from the stock solutionI. Mole fraction of NaCl is 2.79x10⁻³
II. Molarity of NaCl solution is 0.155m
III. 6.49mL of the stock solution required to prepare 100 mL of 0.01 M NaCl solution.
What does % by mass mean?
A solution of 0.90% by mass NaCl means that, in 100g of solution, you have 0.90g of NaCl.
Or
There is 0.90g of NaCl + 99.1g of water.
We need to find:
I. Mole fraction of NaCl:
Mole fraction can is the ratio of moles of Solute to the total number of moles of the solutes and the solvent.
Moles of NaCl(solute) = 0.90g * (1mol / 58.44g) = 0.0154 moles NaCl
Moles of water(solvent) = 99.1g water * (1mol / 18.01g) = 5.50 moles water.
Total moles = 5.50 +0.0154 moles = 5.518 moles
Mole fraction of NaCl = [tex]\frac{0.0154}{ 5.518} =2.79 * 10^{-3}[/tex]
II. Molality is a measure of the number of moles of solute(NaCl) in a solution corresponding to 1 kg or 1000 g of solvent
Since, 99.1g of water = 0.0991kg.
Molality of NaCl = [tex]\frac{0.0154 moles}{0.0991 kg}=0.155m[/tex]
III. 100mL of a 0.01M is:
100mL = 0.100L * (0.01 mol / L) = 1x10⁻³ moles of NaCl
In 100g = 100mL (Density of 1g/mL) there are 0.0154 moles. To have 1x10⁻³ moles you need:
1x10⁻³ moles of NaCl * [tex]\frac{100 mL}{0.0154 moles}[/tex] = 6.49mL of the solution you must add from the stock solution
Learn more:
https://brainly.com/question/15063496
What volume is show in this picture?
Answer:
millileter????
he solubility of oxygen gas in water at 25 °C and 1.0 atm pressure of oxygen is 0.041 g/L. The solubility of oxygen in water at 2.5 atm and 25 °C is ________ g/L.
Answer:
0.1025 g/L
Explanation:
From the question above,
The solubility of oxygen gas in water at 25°c and 1.0 atm pressure is 0.041g/L
Henry's law states at a constant temperature the solubility of a gas is proportional to the pressure
Since the temperatures are both similar (25°c) then, the solubility of oxygen in water at 2.5 atm can be calculated as follows
= 0.041/1.0 × 2.5
= 0.041×2.5
= 0.1025 g/L
Hence the solubility of oxygen in water at 2.5 atm and 25°c is 0.1025 g/L
how can chemistry help solve a crime ?
plz helppp
Chemistry is vital in forensic science (used to solve crimes). With chemistry, forensic scientists demonstrate what happened on a molecular level. Chemical analysis can reveal how long ago a person died, what weapon was used, the kind of tape or rope used to tie someone up, etc. They also analyze drugs/controlled substances taken from scenes and people to identify and sometimes quantify these materials.
MgSO4(aq) + 2NaOH(aq) Mg(OH)2(s) + Na2SO4(aq) i. Write the complete ionic equation from the balanced equation. (3 points) Please help!
Answer:
Mg²⁺(aq) + SO₄²⁻(aq) + 2Na⁺(aq) + 2OH⁻(aq) → Mg²⁺(aq) + 2OH⁻(s) + 2Na⁺(aq) + SO₄²⁻(aq)
Explanation:
The complete ionic equation is the chemical equation where the chemical species in the aqueous phase (aq) are written as ions.
In the reaction:
MgSO₄(aq) + 2NaOH(aq) → Mg(OH)₂(s) + Na₂SO₄(aq)
MgSO₄ dissociates in Mg²⁺ and SO₄²⁻, NaOH in Na⁺ and OH⁻, Mg(OH)₂ doesn't dissociate because is as solid and NaSO₄ dissociates in Na⁺ and SO₄²⁻ ions.
That means the complete ionic equation is:
Mg²⁺(aq) + SO₄²⁻(aq) + 2Na⁺(aq) + 2OH⁻(aq) → Mg²⁺(aq) + 2OH⁻(s) + 2Na⁺(aq) + SO₄²⁻(aq)Why is a 9-v transistor battery used as the source of electrical power for electrolysis rather than the power supply that plugs into the wall electrical current?
Answer:
The 9-v transistor battery is a direct current source, while the power supply from the wall socket is an alternating current source.
Explanation:
A direct current (DC) is one that flows continuously without any minimum and maximum values. This is majorly obtained from generators, batteries or cells etc.
An alternating current (AC) is a type that flows in a sinusoidal manner, having minimum and maximum value with respect to its flowing frequency. An example is the one obtained from the wall electrical source , generators etc.
An alternating current is not mainly used for electrolysis because of its nature. It would cause a switch of the electrodes in every cycle. Therefore, a direct current source is used.
The 9-v transistor battery is a direct current source, while the power supply from the wall is an alternating current source.
calculate the potential of the electrochemical cell and determine if it is spontaneous as written at
Hello. This question is incomplete. The full question is:
Calculate the potential of the electrochemical cell and determine if it is spontaneous as written at 25 ∘C . Cu(s) || Cu2+(0.14 M) ‖‖ Fe2+(0.0040 M) || Fe(s) E∘Cu2+/Cu=0.339 VE∘Fe2+/Fe=−0.440 V Ecell= V Is the electrochemical cell spontaneous or not spontaneous as written at 25 ∘C ? not spontaneous spontaneous
Answer:
Ecell = -0.825v
Negative results indicate that the electrochemical cell is not spontaneous.
Explanation:
You will find the result by doing the following calculation:
Cu2 + = 0.14M
Fe2 + = 0.0040M
Eº Cu2 + / Cu = 0.339V
Eº Fe2 + / Fe = -0.440V
Electron change ............ n = 2
Cu // Cu2 + (0.14M) // Fe2 + (0.0040M) / Fe (s)
Cu + Fe2 + ----> Fe (s) + Cu2 + (aq)
You should now use the formula =
Eºcell = Eº anode - Eº cathode ------> Eº = Eº (Fe2 + / Fe) - Eº (Cu2 + / Cu)
Eº Cell = -0.440 - 0.339 = -0.779V
E cell = EºCell - (0.0591 / n) log (Cu2 + / Fe2 +)
E cell = -0.779 - (0.0591 / 2) log (0.14 / 0.0040)
Ecell = -0.825
Perform the calculation, rounding your answer to the proper number of significant figures.
0.8730 divided by 9.650 =
Answer:
Hey!
0.8730 / 9.650 = 8.42445
Explanation:
8.42445 TO 2 s.f... (best option for rounding)
= 8.4
ANSWER = 8.4 (2 s.f)
HOPE THIS HELPS!!
Convert 1,650,000 centimeters to kilometers.
Answer:
16.5
Explanation:
Answer:
is your answer is 16.5 km
For molecules with multiple ionizable groups, such as glycine, which of the following statements is true?1. At a pH near the pI, nearly all the molecules carry a net positive charge.2. At pH near the pI, nearly all the molecules carry no net charge.3. At a pH near the pI, nearly all the molecules carry a net negative charge.4. When the pH is near the pI, the solution is near its
Answer:
2. At pH near the pI, nearly all the molecules carry no net charge
Explanation:
The general equilibrium for a molecule with multiple ionizable groups could be:
H₃A⁺ ⇄ H₂A + H⁺ ⇄HA⁻ + H⁺⇄A²⁻ + H⁺
Where each equilibrium has its own pKa
The equilibriums in which H₂A are involved (The neutral molecule), are used to determine the isoelectrical point.
The isoelectrical point is defined as the value of pH in which the molecule has no net charge.
Thus, true option is:
2. At pH near the pI, nearly all the molecules carry no net chargeHELP! I WILL GIVE BRAINIEST AND 20 POINTS what is a hypothesis? give an example of a hypothesis
Answer:
By definition:
A supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.A proposition made as a basis for reasoning, without any assumption of its truth.Example:
If I study hard in school, I will get good grades.
Imagine that you're doing an experiment to determine how the running speed
of a hamster depends on the weight of the hamster. When plotting your data,
what variable should be on the y-axis?
A. Speed of hamster
B. Color of hamster
C. Weight of hamster
D. Type of hamster
14 oz (ounces) is the same as how many lbs (pounds)?
Answer:
0.875 Pounds
Explanation:
Formula is
Just divide the mass value by 16
A technician is installing a liquid cooling system for a high-end gaming PC. Which of the following liquids is MOST likely used for cooling?A. Iodine
B. Mercury
C. Thermal paste
D. Oil
Calculate the pH and the pOH of an aqueous solution that is 0.020 M in HCl(aq) and 0.085 M in HBr(aq) at 25 °C.
Is a Animal and Plant cell living
Which ester, when treated with NaOEt, gives this Claisen condensation product? 1. (CH_3)_2CHCH_2CO_2CH_2CH_3 2. (CH_3)_2CHCH_2CH_2CO_2CH_2CH_3 3. (CH_3)_2CHCH_2CH_2CH_2CO_2CH_2CH_3 4. CH_3CH_2CH(CH_3)CH_2CO_2CH_2CH_3
Answer:
( CH_3) _2CHCH_2CH_2CO_2CH_2CH
How many L are in 0.74 CL ?
Answer:
0.0074 cL
7.4 x 10⁻³ cL
Explanation:
Step 1: Find conversion
1 liter (L) = 100 centiliters (cL)
Step 2: Set up dimensional analysis
[tex]0.74cL(\frac{1L}{100cL} )[/tex]
Step 3: Multiply and cancel out units
cL and cL cancel out.
We are left with L.
0.74/100 = 0.0074 cL or 7.4 x 10⁻³ cL