Answer:
250 °C.
Explanation:
From the question given above, the following data were:
Heat (Q) required = 20.0 kilocal
Mass (M) of water = 80 g
Change in temperature (ΔT) =.?
Next, we shall convert 20.0 Kilocalories to calories. This can be obtained as shown below:
1 kilocal = 1000 Cal
Therefore,
20 kilocal = 20 kilocal × 1000 Cal / 1 kilocal
20 kilocal = 20000 calories
Therefore, 20 kilocalorie is equivalent to 20000 calories.
Finally, we shall determine the change in temperature observed as follow:
Heat (Q) required = 20000 Cal
Mass (M) of water = 80 g
Specific heat capacity (C) of water = 1 Cal /gºC
Change in temperature (ΔT) =.?
Q = MCΔT
20000 = 80 × 1 × ΔT
20000 = 80 × ΔT
Divide both side by 80
ΔT = 20000 / 80
ΔT = 250 °C
Therefore, the change in temperature observed is 250 °C
A gas cylinder with a volume of 12.5 L contains 36.3 g of gas. What is the density of the gas?
Density = Blank g/L
Answer:
The answer is 2.90 g/LExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 36.3 g
volume = 12.5 L
We have
[tex]density = \frac{36.3}{12.5} \\ = 2.904[/tex]
We have the final answer as
2.90 g/LHope this helps you
What does it mean to say that the
atoms in a sample of an element are
isotopes of each other?
Answer:
They have the same number of protons, but a different number of neutrons.
Explanation:
All atoms of the same element have the same number of protons, however, they don't necessarily have the same number of neutrons. If atoms of the same element have different numbers of neutrons, they are isotopes of one another. An example is carbon-12 and carbon-13. Carbon-12 has 6 protons and 6 neutrons. Carbon-13 has 6 protons and 7 neutrons. They are isotopes.
which of the following describes a synthesis reaction
Answer: Two reactants combine to form one product.
Explanation: :/
Explain how you could separate a mixture of ocean water (salt water) which has sand in it. You must separate all three substances.
Answer:
Salt and sand can be separated by mixing the two substances with water. The salt will dissolve into the water, while the sand will settle at the bottom of the mixture.
Explanation:
What is the basic unit of stucture and function of living things
PLS HELP ASAP... Assigning the atomic mass of 16.000 to oxygen, what is the atomic mass of sulfur?
Use the hypothetical atom drawings (A-F) below to answer the next four questions. Note there is only one correct choice for each question and each choice is only used once. a.Which shows the absorption of violet light? Explain your reasoning.b.Which shows the emission of blue light? Explain your reasoning.c.Which shows the absorption of green light? Explain your reasoning.d.Which the emission of orange light? Explain your reasoning.e.Which shows an electron being ejected from the atom?
Answer:
a) D
b) C
c) B
d)E
e)A
Explanation:
For clarity, I have attached the images of the transitions to aid understanding.
The visible spectrum consists of Red, Orange, Orange,Yellow Green, Blue,Indigo,Violet. The magnitude of the wavelength of each decreases from left to right in that order. This implies that the red portion of the spectrum is less energetic than the violet portion because energy of a photon increases with decreasing wavelength.
D corresponds to the violet region because the energy difference between the two energy levels is high and requires the absorption of short wavelength, high energy photons of light.
In (b), image C represents an emission that involves a shorter wavelength and can only correspond to blue since it is from a energy level n=3 to n=1
In image (c) , green light is intermediate in energy and will correspond to image B because image F reflects a transition that occurs at a longer wavelength since the energy levels are close together.
In (d) orange light is found at the far, long wavelength portion of the spectrum hence it may involve an n=4 to n=2 transition.
A represents the ionization of the atom, the electron is finally lost from the atom.
How many moles are in a 63.60g sample of carbón
Answer:
5.296 Moles
Explanation:
I literally found this answer in one of my old notebooks if you need I can try to explain it so you can understand.
How many moles are in 1.204 x 10^24 atoms of gold?
Answer:
The answer is 2 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question
N = 1.204 × 10²⁴ atoms of gold
We have
[tex]n = \frac{1.204 \times {10}^{24} }{6.02 \times {10}^{23} } \\ [/tex]
We have the final answer as
2 molesHope this helps you
Carla did an experiment by placing a piece of smooth clear glass in a piece of smooth Black Stone under a lamp for 20 minutes which prediction will most likely be supported by Carlas experiment results
A. the glass will feel warmer than the stone after 20 minutes
B. The stone will feel warmer than the glass after 20 minutes
C. The glass will reflect all of the light after 20 minutes
D. The stone will reflect all of the light after 20 minutes
Answer:
b
Explanation:
The stone will feel warmer than the glass after 20 minutes.
What is Conduction?This can be defined as a process of heat transfer which involves direct contact between the objects.
The stone and the lamp in contact with each other means heat will be transferred to the stone thereby making it warmer and the reason why option B was chosen as the most appropriate choice.
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Who was on the grand committee
Answer:
European Union was on grand committee
Answer:
European Union
Explanation:
hehe
For the 52nd electron must pair with one of the
electrons in the 5p orbital.
Answer:
This question is incomplete
Explanation:
This question is incomplete, however, the element that has 52 electrons only is Tellurium (Te) and when the electronic configuration of elements with more than 52 electrons are written, the 52nd electron is indicated/paired the same way the 52nd electron of Te is indicated/paired. Hence, while writing the electronic configuration of Te, it is written as
[Kr] 4d¹⁰ 5s² 5p⁴ where [Kr] is the electronic configuration of krypton. Based on this, we can deduce that the 52nd electron will be in the first orbital of the P subshell (as attached in the picture). This is because when indicating the electrons in the subshell, one electron will be spread across each orbital and if any electron is still remaining, it will be added starting from to the first orbital of the subshell, however no two electrons in an orbital in a subshell can have the same spin and hence must face opposite direction based on pauli's exclusion principle (as seen in attached); thus for the 5p-orbital of elements with 52 or more electrons, when one electron each is represented in each box (3 boxes in total) in the 5p-orbital, the remaining electron is paired with the the first electron in the first box of the 5p-orbital
Which of these is an example of a physical change?
Sugar dissolving in Warm water
Iron rusting in the presence of moist air
Wood burning in the presence of oxygen
Baking soda reacting with acid to form a gas
Answer:
hope it helps you❤❤❤
Explanation:
The physical change would be the sugar dissolving in water because no reaction is occurring.
sugar dissolving in warm water is an example of physical change.
physical change is doesn't alter the composition or the identity of the substance .
That's mean when you dissolves sugar in water, after a while the object will be the same which mean that the component doesn't change
What pH might you expect from a weak acid and a strong base if equal concentrations ?
13.5
7.0
3.2
10.4
Answer:
7.0
Explanation:
In the titration of a weak acid and a strong base, the pH or equivalence point will be greater than 7. Therefore, option D is correct.
What is pH?The pH of the solution can be described as the negative logarithm of hydrogen ions (H⁺) concentration. Mathematically, the pH value is generally inversely proportional to the hydrogen ion's concentration.
pH = -log ([H⁺])
In chemistry, the pH scale is used to determine the basicity or acidity of an aqueous solution. Acidic solutions can be calculated to have lower pH values than alkaline solutions.
The pH scale has a scale of 0 to 14 while pH 7.0 is neutral. A low pH of about 1 or 2 is acidic and a high pH of 12 or 14 is basic.
The pH value of the weak acid and a strong base solution will be greater than seven because the conjugate base of a weak acid is weakly basic. Therefore, the expected pH from a weak acid and a strong base if equal concentrations will be greater than 7 can be 10.4.
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Which is the SI symbol for volume?
Answer:
In the International System of Units (SI), the standard unit of volume is the cubic metre (m3). The metric system also includes the litre (L) as a unit of volume, where one litre is the volume of a 10-centimetre cube.
Explanation:
i think
4.3 moles of Ra(OH)2 to grams
8. Give the symbol of and the number of neutrons in one atom of:
(Round the MASS numbers so they are ALWAYS whole numbers…show your calculations)
Beryllium _____________ _________________
Calcium _______________ _______________
Sulfur _______________ ______________
Answer:
Explanation:
Given species;
Beryllium
Calcium
Sulfur
Unknown:
Give the symbol, number of neutrons and the mass number
Solution:
The symbols of the species are;
Beryllium - Be
Calcium - Ca
Sulfur - S
Number of neutrons:
Beryllium - 5
Calcium - 20
Sulfur - 16
Mass number :
Beryllium - 9
Calcium - 40
Sulfur - 32
A chem 1515 student was given a solution of the cations X3 , Y2 , and Z in the form of nitrates. Through a series of tests, she obtained the following information:
Reagent X3 Y2 Z
Na2SO4 No Reaction Forms white ppt. Brown ppt. forms
NH4OH No Reaction No Reaction ppt. Dissolves
HCl No Reaction No Reaction White ppt. forms
Na3PO4 White ppt. forms No Reaction No Reaction
The reaction between Z (aq) and Na2SO4 forms a brown ppt.
Required:
Write a balanced chemical equation for all of the reactions which result in the formation of a precipitate
Answer:
[tex]2Z^+ (aq) + SO^{2-} _{4} (aq) = Z_{2} SO_{4}[/tex]
Explanation:
The reaction between Z(aq) and Na2SO4 forming a brown ppt shows that the product formed from this reaction is a solid. and also it can be seen that Z+ is a monocationic while SO4 is dianionic, hence molecules (2) of Z+ will combine with (1) molecule of SO4
below is the balanced chemical equation for this reaction
[tex]2Z^+ (aq) + SO^{2-} _{4} (aq) = Z_{2} SO_{4}[/tex]
If the pH of a solution increases by 2 units (e.g., from 3 to 5), then the ratio of the new to the original hydronium ion concentration is
Answer:
This question is incomplete
Explanation:
This question is incomplete. However, generally hydronium ion (H₃O⁺) is produced when hydrogen ion (usually from an acid) is attracted to the negative pole of water (which is the oxygen part).
To determine the ratio in this case is simple, the ratio of the new to the original hydronium ion concentration is;
the calculate new concentration of hydronium ion, [H₃O⁺]
pH = -log[H₃O⁺] hence,
[H₃O⁺] = log⁻¹pH (meaning antilog of pH)
Kindly note that the pH to be used here is 2 + the original pH given
Hence, if the original pH given is 2
The new [H₃O⁺] will be 4
[H₃O⁺] = log⁻¹ 4
= 10000
Same formula should be used to determine the concentration of the original hydronium ion concentration using the original pH given.
Hence, [H₃O⁺] = log⁻¹ 2
= 100
The ratio of the new to the original hydronium ion concentration will be
10000:100
100:1
The ratio of the new to the original hydronium ion concentration when the pH of a solution increases by 2 is; 1: 100
The Hydroxonium ion is similar to the hydrogen ion concentration and is written as;. {H3O+¹}.
The formula for calculating the pH of a solution is;
pH = -log {H3O+¹}When the pH increases by 2 units; (e.g., from 3 to 5).
Therefore; By evaluation;
at pH = 3; {H3O+¹} = 10-³and at pH = 5; {H3O+¹} = 10-⁵.Therefore; 10-⁵/10-³ = 10-².
In essence; the ratio of the new to the original hydronium ion concentration is; 1 : 100
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Will do brainliest! Atoms of two different elements must have different
electrical charges.
numbers of neutrons.
atomic numbers.
energy levels.
Please
the answer is atomic number
Answer:
atomic numbers
Explanation:
In order for two atoms to be different, they have to have a different number of protons. Protons are represented by the atomic number. Thus, atoms of two DIFFERENT elements must have different atomic numbers.
I took the test and got 100%
Hope this helps!
Particles in a block of iron are stationary (not moving).
True
False
Answer:
False,
but it depends of the meaning of the word particle
Explanation:
even if it's a metallic bounding, or if it's very solid, has low temperature, and has a very high electrostatic force of its atoms, its particles will have some kind of movement, because it has temperature, that means that it has some kind of Agitation
Particles in a block of iron are stationary. That is true.
The particles in a block of iron are stationary depending on the temperature of the block of iron. Since the block of iron is a solid and particles of a solid tend to have low kinetic energies at low temperatures, then at low temperatures, the particles in the block of iron would be stationary.
So, Particles in a block of iron are stationary. That is true.
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what is the change in enthalpy in kilojoules when 3.24 g of CH3OH is completely reacted according to the following reaction 2 CH3OH -->4 CH4 + O2 ∆H
=252.8 Kj
Answer:
12.78 kJ
Explanation:
The correct balanced reaction would be
[tex]2CH_3OH\rightarrow 2CH_4+O_2\Delta H=252.8\ \text{kJ}[/tex]
Mass of methanol = [tex]3.24\ \text{g}[/tex]
Moles of methanol can be obtained by dividing the mass of methanol with its molar mass [tex](32.04\ \text{g/mol})[/tex]
[tex]\dfrac{3.24}{32.04}=0.10112\ \text{moles}[/tex]
Enthalpy change for the number of moles is given by
[tex]\dfrac{\text{Number of moles of methanol in the reaction}}{\text{Enthalpy change in the reaction}}=\dfrac{\text{Number of moles in 3.24 g of methanol}}{\text{Enthaply in change in the mass of methanol}}[/tex]
[tex]\\\Rightarrow\dfrac{2}{252.8}=\dfrac{0.10112}{\Delta H}\\\Rightarrow \Delta H=\dfrac{0.10112\times 252.8}{2}\\\Rightarrow \Delta H=12.781568\approx 12.78\ \text{kJ}[/tex]
The change in enthalpy is 12.78 kJ.
When 3.24 g of CH₃OH are decomposed, the change in the enthalpy is 12.8 kJ.
Let's consider the following thermochemical equation.
2 CH₃OH ⇒ 4 CH₄ + O₂ ∆H = 252.8 kJ
First, we will convert 3.24 g of CH₃OH to moles using its molar mass (32.04 g/mol).
[tex]3.24 g \times \frac{1mol}{32.04g} = 0.101 mol[/tex]
According to the thermochemical equation, 252.8 kJ are absorbed when 2 moles of CH₃OH react. The enthalpy change when 0.101 moles of CH₃OH react is:
[tex]0.101 mol \times \frac{252.8 kJ}{2mol} = 12.8 kJ[/tex]
When 3.24 g of CH₃OH are decomposed, the change in the enthalpy is 12.8 kJ.
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Which quantity increases as a free-falling object approaches Earth's surface?
a, momentum
b. stopping force
c. both momentum and stopping force
d. neither momentum nor stopping force
Answer:
a momentum
Explanation:
because it appears Earth's surface
On approaching the earth's surface, the momentum of the object increases. Thus, option A is correct.
The momentum can be defined as the velocity of the specific mass of the object. The stopping force has the force acting in the opposite direction of the force applied to reduce the acting force.
When an object has been approaching the earth's surface there has been an increase in the mass of the object with respect to the gravity force. The increase in mass results in the increase in the momentum of the object.
Thus, on approaching the earth's surface, the momentum of the object increases. Thus, option A is correct.
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Please help! I'm so confused
Answer:
screwdriver,fork,key,screw
Explanation:
the key is made of either copper or a different metttal or conducter just like the other objects are made of a semiconducting material
If I have 0.376 g of air, what are the moles of air, and what is the molar mass of air (g/mol)?
Please show how to get the answer.
Answer:
10.88g
Explanation:
The main components of dry air are N2 at 78.08% vol , O2 at 20.95% vol, and Argon at 0.934% vol. We will not be concerned with the lesser components because they will not have a significant effect on our answer. First we need to find the molar mass of dry air so we use the formula Mass = (percent mass * molar mass of gas) we then plug and chug: MM = (0.7804 * 28.01) + (0.2095 * 31.99)+(0.00934 * 39.95) which gives MM = 28.93 mol/gram
Now that we have the molar mass we use conversion factors to get 0.376g / 28.93mol = 10.88g
Gaseous mixtures ________. Question 1 options: can only contain molecules must contain both isolated atoms and molecules are all homogeneous are all heterogeneous can only contain isolated atoms
Answer:
Must contain isolated both isolated atoms and molecules
Explanation:
There is very little intermolecular forces of attraction between atoms and molecules of a gas.
Hence in a gas mixture; We mostly find isolated atoms and molecules with minimal interaction with each other, hence the answer.
help and explain how to convert it pls
Answer : The correct answer is option (3) [tex]5.68\times 10^{-19}J[/tex]
Explanation: Given,
Wavelength = 350 nm = [tex]350\times 10^{-9}m[/tex] [tex](1nm=10^{-9}m)[/tex]
Now we have to determine the energy of photon.
Formula used:
[tex]E=\frac{hc}{\lambda}[/tex]
where,
E = energy of photon
h = Planck's constant = [tex]6.63\times 10^{-34}J.s[/tex]
c = speed of light = [tex]3\times 10^{8}m/s[/tex]
[tex]\lambda[/tex] = wavelength of photon
Now putting all the given values in this formula, we get:
[tex]E=\frac{(6.63\times 10^{-34}J.s)\times (3\times 10^{8}m/s)}{350\times 10^{-9}m}[/tex]
[tex]E=5.68\times 10^{-19}J[/tex]
Therefore, the energy of photon is, [tex]5.68\times 10^{-19}J[/tex]
Which best explains why a black T-shirt gets warmer in the Sun than a white T-shirt?
Group of answer choices
Darker colors reflect more energy from electromagnetic waves than lighter colors do.
Darker colors reflect more energy from colliding particles than lighter colors do.
Darker colors absorb more energy from electromagnetic waves than lighter colors do.
Darker colors absorb more energy from colliding particles than lighter colors do.
Answer:
the color black absorbs energy which in turn will make u hot. the color white reflects energy which in turn will keep u cool
Explanation:
Answer:
The answer is c
Explanation:
The answer is c because dark colored clothes absorb more electromagnetic waves than a white t-shirt because lighter only reflects
Assign an oxidation number to each atom in the reactants.
4Al(s)+3O2(g)→2Al2O3(s)
(Oxidation number for both Al and O is needed)
Answer:
Al⁺³ , O⁻²
Explanation:
This is an oxidation reduction reaction (Redox).
Chemical reaction:
4Al + 3O₂ → 2Al₂O₃
The oxidation state on Al and O on left hand side is zero. On right hand side Al is present in +3 oxidation state while O is present in -2 oxidation sate.
Oxygen is reduced and Al is oxidized in this reaction.
The oxidation reduction reactions are called redox reaction. These reactions are take place by gaining or losing the electrons and oxidation state of elements are changed.
Oxidation:
Oxidation involve the removal of electrons and oxidation state of atom of an element is increased.
Reduction:
Reduction involve the gain of electron and oxidation number is decreased.
As an apple falls from a tree, which types of energy are changing?
Group of answer choices
Elastic energy and sound energy
Light energy and gravitational potential energy
Kinetic energy and nuclear energy
Gravitational potential energy and kinetic energy