Answer:
0,5 seconds = 500 millisecondes
2 km = 200 meters
Explanation:
A sample of 0.562 g of carbon is burned in oxygen in a bomb calorimeter, producing carbon dioxide. Assume both the reactants and products are under standard state conditions, and that the heat released is directly proportional to the enthalpy of combustion of graphite. The temperature of the calorimeter increases from 26.74 °C to 27.93 °C. What is the heat capacity of the calorimeter and its contents?
Answer:
The correct answer is 15.54 kJ per degree C.
Explanation:
The enthalpy change for one mole of a substance, which combines or burns with the oxygen under the standard conditions, that is, at 25 degree C and 1 bar pressure is known as the standard molar enthalpy of combustion. The amount of heat transferred can be calculated by using the formula, q = mcΔT -------------(i)
Here q is the amount of heat transferred, c is the specific heat, ΔT is the change in temperature, and m is the mass of the substance. As in case of bomb calorimeter, mass if considered constant, thus, for calorimeter the equation mentioned will become, q = cΔT ---- (ii)
The standard molar enthalpy of combustion for carbon is -393.5 kJ/mol, that is, -393.5 kJ per mole of heat is generated by burning one mole of carbon. The molecular mass of carbon is 12 gram per mole.
Thus, the number of moles of carbon equivalent to 0.562 grams of carbon can be determined as,
Number of moles of carbon = mass / molecular mas
= 0.562 grams / 12 gram per mole
= 0.047 mol
The heat generated by burning 0.562 grams or 0.047 mole will be,
q = ΔH° × number of moles
= (-393.51 kJ/mol) × 0.047 mol
= -18.49 kJ, the negative sign shows that the heat is produced.
To find heat capacity of calorimeter, put the value of q as -18.49 kJ, for ΔT as (27.93 °C - 26.74 °C) in the equation (ii)
18.49 kJ = c × (27.93 - 26.74)
c = 18.49 kJ/1.19 °C
c = 15.54 kJ/°C
Explain why the first ionisation energy of helium is
larger than that of hydrogen.
Answer
Explanation:
helium has a structure 1s² the electrons are removed from the same orbital as in case of hydrogen the electrons are closest to the nucleus the value of ionization energy of helium is much higher than hydrogen because the nucleus now has 2 proton attracting the electrons instead of 1 in case of hydrogenWhich is the correct definition of metallic bonding? Select one: a. an array of positive ions in a sea of electrons b. complete transfer of valence electrons c. atoms share electrons to to be stable
Answer:
I believe it's A) an array of positive ions in a sea of electrons
A 1.30 L buffer solution consists of 0.107 M butanoic acid and 0.345 M sodium butanoate. Calculate the pH of the solution following the addition of 0.075 moles of NaOH . Assume that any contribution of the NaOH to the volume of the solution is negligible. The Ka of butanoic acid is 1.52×10−5 .
Answer:
The pH of the solution following the addition of 0.075 moles of NaOH is 5.7.
Explanation:
The equation of the buffer solution is the following:
C₄H₇O₂H(aq) + H₂O(l) ⇄ C₄H₇O₂⁻(aq) + H₃O⁺(aq) (1)
The pH of the buffer solution can be found using the Henderson-Hasselbalch equation:
[tex] pH = pKa + log(\frac{[NaC_{4}H_{7}O_{2}]}{[C_{4}H_{8}O_{2}]}) [/tex] (2)
The NaOH added will react with butanoic acid tot produce sodium butanoate:
C₄H₇O₂H(aq) + OH⁻(aq) ⇄ C₄H₇O₂⁻(aq) + H₂O(l) (3)
[tex] n_{C_{4}H_{7}O_{2}H}_{i} = C*V = 0.107 M*1.30 L = 0.139 moles [/tex]
[tex] n_{C_{4}H_{7}O_{2}^{-}} = 0.345 M*1.30 L = 0.449 moles [/tex]
[tex] n_{NaOH} = 0.075 moles [/tex]
[tex] n_{C_{4}H_{7}O_{2}H} = 0.139 moles - 0.075 moles = 0.064 moles [/tex]
[tex] n_{C_{4}H_{7}O_{2}^{-}} = 0.449 moles + 0.075 moles = 0.524 moles [/tex]
[tex]C_{C_{4}H_{7}O_{2}H} = \frac{0.064 moles}{1.30 L} = 0.049 M[/tex]
[tex] C_{C_{4}H_{7}O_{2}^{-}} = \frac{0.524 moles}{1.30 L} = 0.403 M [/tex]
Now, from equation (1) we have:
C₄H₇O₂H(aq) + H₂O(l) ⇄ C₄H₇O₂⁻(aq) + H₃O⁺(aq)
0.049 - x 0.403 + x x
[tex] Ka = \frac{[C_{4}H_{7}O_{2}^{-}][H_{3}O^{+}]}{C_{4}H_{7}O_{2}H} [/tex]
[tex]1.52 \cdot 10^{-5} = \frac{(0.403 + x)x}{0.049 - x}[/tex]
[tex]1.52 \cdot 10^{-5}*(0.049 - x) - (0.403 + x)x = 0[/tex]
By solving the above equation for x we have:
x = 1.85x10⁻⁶ = [H₃O⁺]
So, the concentration of butanoic acid and sodium butanoate is:
[tex][C_{4}H_{7}O_{2}^{-}] = 0.345 + 1.85 \cdot 10^{-6} = 0.345 M[/tex]
[tex][C_{4}H_{7}O_{2}H] = 0.049 - 1.85 \cdot 10^{-6} = 0.049 M[/tex]
Finally, from equation (2) we have:
[tex] pH = pKa + log(\frac{[NaC_{4}H_{7}O_{2}]}{[C_{4}H_{8}O_{2}]}) [/tex]
[tex]pH = -log(1.52 \cdot 10^{-5}) + log(\frac{0.345}{0.049}) = 5.7[/tex]
Therefore, the pH of the solution following the addition of 0.075 moles of NaOH is 5.7.
I hope it helps you!
Plz help me...!!! I need this answer by today!....
What is the weight of a 98 kg astronaut on the Mars where the value of the gravitational pull is 3.711 m/s2?
What is his mass on earth? What is his weight on Venus where the gravitational pull is 8.87 m/s2?
Answer:
Explanation:
given mass on earth =98 kg
gravitational pull on mars =3.711 m/s2
gravitational pull on venus =8.87 m/s2
weight of the body on mars =weight on earth/9.81 m/s2 *3.711 m/s2
W=98 kg*3.711 /9.81m/s2
W=37.07 kg
weight on the venus =weight on earth*8.87 m/s2 /9.81 m/s2
W= 98 kg*7.87 m/s2/9.81 m/s2
W=78.62 kg
PLEASE HELP!! What direction do you predict the addition of a base to the solution containing bromophenol blue will drive the equilibrium? Explain your prediction in terms of Le Châtelier's principle.
Answer:
Below is the clarification of that same particular question.
Explanation:
Le Chatlier's theory states that whenever an equilibrium mechanism is disrupted by environmental influences, the program responds by changing the supplies information of its constituents in a somewhat way that the disturbance is invalidated and reaches a stable equilibrium during that disrupted stage, with concentrations of stability differently than ever before.Bromothymol blue seems to be a phenolic subs lone which always allows it to act throughout aqueous solutions as an acidic solution. Being such an acid (weak), it should not add to rapid, as well as introduces a balance with its accompanying but mostly disconnected form.For that kind of weak diprotic predictor, the standard economic statement can indeed be published as:
⇒ [tex]H_2In_(aq)\rightleftharpoons In^{2-} +2H^+[/tex]
It could be conclusively proven from either the theory of Le Charlier whereby, that whenever a strong acid becomes applied, the full disorientation of one or the other, through equilibrium formation, induces an increase throughout the medium's proton concentrations.Likewise, it absorbs the protons throughout the media to split water that whenever a solution is added. So, particle concentration throughout the medium is decreasing. To accommodate for this transition, the equilibrium reacts by moving to the correct i.e. causing further dissociation of the optimistic predictor into their dianion through protons, thereby attempting to nullify that perturbation.If a sample of aluminum with a density of 2.70 g/cm^3 displaces 36.0 mL of water when placed in a beaker, what is its mass?
13.3 g
97.2 g
0.075 g
Answer:
The answer is 97.2g .
Explanation:
Given that 1 mL is equals to 1 cm². Then we have to apply Density formula :
[tex]density = \frac{mass}{volume} [/tex]
[tex]let \: density = 2.7 \: , \: volume = 36[/tex]
[tex]2.7 = \frac{mass}{36} [/tex]
[tex]mass = 2.7 \times 36[/tex]
[tex]mass = 97.2 \: grams[/tex]
HELP!!!!!!, I need this urgently!!!
Compare the properties of producer and water gas
Answer:
Producer gas and water gas contain carbon monoxide and hydrogen.
Suppose you see an advertisement for a video game that claims you can actually fly around inside your home while you play it. What do your scientific literacy and critical thinking skills lead you to think about that claim?
Answer:
Scientific literacy and critical thinking skills will nullify the claims made in the advertisement.
Explanation:
The claims made in the advertisement contradict the scientific laws and the person who understands the scientific theories can easily understand that. Critical thinkers may derive rational insights from a collection of facts, and distinguish between relevant and less important reasons for problem-solving or decision making. Therefore on objectively evaluating scientific theories, we conclude to a rational decision, that is the claims are false.
A pharmaceutical company is making a large volume of nitrous oxide (NO). They predict they will be able to make a maximum amount of 4860 grams with the materials they have in stock. From the previous 10 volumes they have made, they know that the percent yield of this reaction is fairly low at 47%. How much will the actual yield be? A. 228 grams B. 2284 grams C. 10340 grams D. 486 grams
Answer:
The answer is "Option B"
Explanation:
From the query, the following knowledge is derived:
Yield in percentage = 47%
Performance of theory = 4860 g
Actual yield Rate =?
The percentage return is defined simply by the ratio between both the real return as well as the conceptual return multiplied by the 100. It's also represented as numerically:
[tex]Rate = \frac{Existing \ Rate} {Theoretical \ Rate} \times 100[/tex]
Now We can obtain the percent yield as followed using the above formula:
[tex]\text{Yield in percentage}= \frac{Actual \ yield \ Rate} {Theorical \ Rate} \times 100[/tex]
[tex]47\% = \frac{Actual \ yield \ Rate}{4860}[/tex]
The value of the Actual yield Rate =[tex]47\% \times 4860[/tex]
[tex]= \frac{47}{100} \times 4860 \\\\ = 2284.2 g[/tex]
The Actual yield Rate= 2284.2 g.
2. Bottled Italian salad dressing is an example of *
O a suspension
a colloid
a solution
O a homogeneous mixture
4. The mass of a silver liberty (coin) was measured three times and each measurement was made
to five digits. The mass values were 12.519 9.12.521 g, and 12.496 g. The average mass was
reported as 12.512 g.
Why is the average mass of the gold coin reported to five significant figures, even though you
had to divide by "3" to obtain the average?
Answer:
The average mass of the gold coin reported to five significant figures, even though you had to divide by "3" to obtain the average.
Explanation:
Given that,
The mass of a silver liberty was measured three times and each measurement was made to five digits.
The mass values are,
[tex]m_{1}=12.519\ g[/tex]
[tex]m_{2}=12.521\ g[/tex]
[tex]m_{3}=12.496\ g[/tex]
The average mass of the gold coin is 12.512 g.
We know that,
Significant figures :
Significant figures is explained the nonzero, leading zero and zeros between two nonzero digits.
For example,
The digits is 0.003405
In the digit, 345 = nonzero
0.00 = leading zero
The average mass of the gold coin reported to five significant figures because average mass is 12,512. All digits are nonzero.
Nonzero digit are significant.
Hence, The average mass of the gold coin reported to five significant figures, even though you had to divide by "3" to obtain the average.
Drag each characteristic to the correct category. Viruses do not possess all the characteristics of life. Identify those characteristics that viruses display and those they don't display.
Answer:
Virus is living due to reproduction and non-living due to crystal appearance.
Explanation:
Characteristics that viruses display is the ability of reproduction in which they increase in population which is a living character and have DNA or RNA which help them to make exact copies of itself. Virus is parasitic in nature because it causes harm to the living host such as humans, animals and plants. Some characteristics that viruses don't display are that they are not like living cells, have no membrane around them, no organelles such as mitochondria, golgi bodies, endoplasmic reticulum and lysosomes etc. Viruses are present in crystal form outside the cell.
Which is not a characteristic of all metals? Select one: a. soft and easy to cut b. Good electrical conductors c. Ductile and malleable
Use the following steps to balance the redox reaction using half-reactions. Zn(s) + Fe3+ Zn2+ + Fe(s) (unbalanced) a. Write balanced oxidation and reduction half-reactions. Indicate which is the oxidation reaction and which is the reduction reaction. (6 points) b. Balance the charge in the two half-reactions by multiplying the half-reactions by the correct multiplication factors. (4 points) c. Add the equations and simplify to get the balanced equation.
Answer:
Explanation:
a )
Zn = Zn²⁺ + 2e ( oxidation reaction )
Fe³⁺ + 3e = Fe( s ) ( reduction reaction )
b )
[ Zn = Zn²⁺ + 2e ] x 3
[ Fe³⁺ + 3e = Fe( s ) ] x 2
-------------------------------------------------------------------
3 Zn + 2 Fe³⁺ + 6e = 3 Zn²⁺ + 2 Fe ( s ) + 6e
3 Zn + 2 Fe³⁺ = 3 Zn²⁺ + 2 Fe ( s )
A student is reading the volume from a standard 50-mL buret identical to what you used in the lab. The bottom of the meniscus is exactly on the 20-mL line. What should she record as the correct volume
Answer:
20 mL
Explanation:
The student should record 20 mL as the correct volume.
The curved surface of a liquid that is usually observed in a buret is referred to as the meniscus. This meniscus is created as a result of the surface tension of the liquid against the walls of the buret. Hence, in order to avoid errors due to parallax, the bottom of the meniscus should be read and not the top.
Therefore, the correct volume that the student should record is 20 mL.
Was is meant by the term suprenatural? Does science deal with the supernatural?
A. The term supernatural literally means (within nature) Science deals with the supernatural because it works within nature, not above it
B. The term supernatural literally means (above nature) Science does not deal with the supernatural because it works within nature, not above it
C. The term supernatural literally means (within nature) Science does not deal with the supernatural because it works above nature, not within it
D. The term supernatural literally means (above nature) Science deals with the supernatural because it also works with nature, not within it
Answer:
it's option D
What does empirical fomula means with examples
urgent plz help thanks!
Which statement best describes a compound formed by an ionic bond?
A) negatively charged
B) neutral
C) contains multiple charges
D) positively charged
Answer:
B. Neutral
Explanation:
When there is a ionic bond, one element steals or takes away an electron from the other element.
An example is NaCl
In this compound, Chlorine atom steals an extra electron from Sodium to fill its outer shell. So, this is a Ionic bond. Since, the Sodium compound gives away an atom, it is positively charged. Since, Chlorine steals an atom, it is negatively charged. Opposite charges attract, so they become a compound.
When positive and negative mix, it becomes neutral.
Balance the chemical equations: 1) ___ N2O5 → ___ N2 + ___ O2 2) _____Fe + _____O2 → _____ Fe2O3 3) _____H2 + _____Cl2 → _____HCl
Answer:
2N2 + 5O2 => 2N2O5
4Fe + 3O2 => 2 Fe2O3
H2 + Cl2 => 2 HCl
Explain why chlorine is a gas while iodine is a solid yet both are halogens. Select one: a. Both iodine and chlorine differ in strength of metallic bonds b. Chlorine has strong inter molecular forces than iodine c. Iodine molecules are large with strong inter molecular forces than chlorine
Answer:
Chlorine has strong inter molecular forces than iodine
Explanation:
Answer:
Chlorine has strong inter molecular forces than iodine
Explanation:
I2 is a solid while Cl2 is a gas because Iodine molecules are larger and therefore experience stronger intermolecular forces.
HOPE IT HELPS :)
PLEASE MARK IT THE BRAINLIEST!
A mixture of gasoline and air explodes when it encounters a spark. This is
known as
O A. a synthesis reaction
O O O
B. a precipitation reaction
C. fuel efficiency
o
D. a combustion reaction
SUBMI
Answer:
D. A combustion reaction
Explanation:
Tips for memorizing the first 20 elements of the periodic table?
Answer:
hydrant flying with balloon, balloon has lithp letting air out, bee: really yum balloon
= = = =
hydrogen helium lithium beryllium
be bore on the balloon, balloon pops, hydrant drops and makes a car bomb
= =
boron carbon
night row general gets hurt by car bomb nearby, that general gets off boat
=
nitrogen
wearing oxygen mask, mask is full of fluride gel, then he got neon teeth
= = =
oxygen fluorine neon
(try making a story out of the elements, use your imagenation)
I will give u tips to learn whole periodic table
1. Break down the table into sections
2. Spread out the memorisation process
3. Learn the elements in a song
4. Make none sense words made from element symbols
5. Use colour to learn element groups
6. Use mnemonic device to help remember the order of elements
I am sure this will be helpful for uuu
Explanation:
Answer the question in attachment and can I ask from which country you are.
I am new on this app.
✌️✌️☺️☺️
Answer:
1: exothermic
2:hydrated iron (III) oxide
3:reactants
4:precipitate
5: hydrogen gas
Answer:1.exothermic
2.hydrated iron (III) oxide
3.reactants
4.precipitate
5. hydrogen gas
8.310x10^2 – 7.210x10^1
[?]x10^[?]
Answer:
[tex]7.589\times 10^{2}[/tex]
Explanation:
The expression can be solved mathematically as follows:
1) [tex]8.310\times 10^{2}-7.210\times 10^{1}[/tex] Given
2) [tex]8.310\times 10^{1+1} - 7.210\times 10^{1}[/tex] Definition of sum
3) [tex](8.310\times 10^{1})\times 10^{1}-7.210\times 10^{1}[/tex] [tex]a^{m+n} = a^{m}\cdot a^{n}[/tex]/Associative property
4) [tex](8.310\times 10^{1}-7.210)\times 10^{1}[/tex] Distributive property
5) [tex](83.100-7.210)\times 10^{1}[/tex] Multiplication
6) [tex]75.89\times 10^{1}[/tex] Subtraction.
7) [tex](7.589\times 10^{1})\times 10^{1}[/tex] Multiplication/Associative property
8) [tex]7.589\times (10^{1}\times 10^{1})[/tex] Associative property
9) [tex]7.589\times 10^{2}[/tex] [tex]a^{m+n} = a^{m}\cdot a^{n}[/tex]/Result
what is the relative formula mass of phosphate (PO4)? (To the nearest tenth) A. 187.9 grams B. 46.9 grams C. 23.0 grams D. 94.9 grams
Answer:
[tex]\huge\boxed{94.9\ grams}[/tex]
Explanation:
Relative formula mass of phosphate:
=> [tex]PO_{4}[/tex] [Ignoring the charge on it]
Atomic mass of P = 31.0 grams, O = 15.9 grams
=> 30.97 + 4(15.9)
=> 30.97 + 63.9
=> 94.87
≈ 94.9 grams [To nearest tenth]
Answer:
[tex]\huge \boxed{\mathrm{D. \ 94.9 \ grams}}[/tex]
Explanation:
Phosphate chemical formula is given as,
[tex]\sf PO_4[/tex]
There is one phosphorus atom and four oxygen atoms.
Atomic mass of Phosphorus [tex]\sf P[/tex] = 30.974 grams
Atomic mass of Oxygen [tex]\sf O[/tex] = 15.999 grams
[tex]\Rightarrow 30.974 + 4(15.999)[/tex]
[tex]\Rightarrow 30.974+ 63.996[/tex]
[tex]\Rightarrow 94.97[/tex]
The relative formula mass of phosphate [tex]\sf PO_4[/tex] is 94.9 grams.
c. CaCl2 can be melted to produce calcium metal and give off chlorine gas. The equation for this
is CaCl2()→ Ca(s) + Cl2(g). If 277.45 g CaCl2 were melted, how many grams of Ca(s) would
be formed? (10 points)
HELP MEEEEE PLEASE
Answer:
Total gram of Ca = 99.26 g
Explanation:
Given:
Mass of CaCl₂ = 277.45 g
Find:
Mass of Ca
Computation:
Ca = 40 g/mol
Cl₂ = 2 (35.5) g/mol = 71 g/mol
Total CaCl₂ = 111 g/mol
Total gram of Ca = [40 / 111] 277.45 g
Total gram of Ca = 99.26 g
PLEASE PLEASE HELP!!!! What is the mass of a sample material that has a volume of 72.2cm³ and a density of 7.7g/cm³?
Answer:
The answer is
555.94g
Explanation:
To find the mass of a substance given it's density and volume we use the formula
[tex]Density \: = \frac{mass}{volume} [/tex]Making mass the subject we have
mass = Density × volume
From the question
Density = 7.7 g/cm³
Volume = 72.2 cm³
Substitute the values into the above formula
That's
mass = 7.7 g/cm³ × 72.2 cm³
We have the final answer as
mass = 555.94gHope this helps you
If alkali A has a pH value of 13 and alkali B has a pH value of 9, explain which is most likely to be used in indigestion tablets as a remedy for excess stomach acid. *
Answer:
Alkalai B
Explanation:
B because its a weak alkali ie baking soda ph 8.3(sodium bicarbonate)which is used as a remeady of heartburns and stomach acids.
How would removing invasive species from an
ecosystem help reduce the chances of a native
species becoming extinct?
A
The native species would go extinct
sooner.
B
The native species would no longer be
infected by diseases
C
The native species would be better adapt
for survival.
D
The native species would not have to
compete for necessary resources,
The correct answer is D. The native species would not have to compete for necessary resources
Explanation:
Invasive species, which include any living organism that is not native in an ecosystem, contribute to the extinction of native species as they compete for resources such as food, shelter, etc. with native species. For example, the Asian Carp, which was introduced to lakes in the U.S. consumes plankton, which reduces the amount of plankton available for native fish. In this context, by removing invasive species native species would not have to compete for resources and their chances to extinct will fall.
