Answer:
An element is a material that consist of a single type of atom . each atom type contains same number of protons . chemical bonds link elements to form more complex molecules called compound A compound consist of two or more elements held together by covalent or ionic bonds.
are you clear?
Hydrogen atoms are excited by a laser to the =4 state and then allowed to emit.
What is the maximum number of distinct emission spectral lines (lines of different wavelengths) that can be observed from this system? Calculate the wavelength of the 4⟶3 transition.
Answer:
1875 nm
Explanation:
Given the Rydberg formula for hydrogen: 1/λ = R(1/n₁² - 1/n₂²)
where R ≈ 1.097* 10^7 /m
Hence;
1/λ = 1.097* 107/m * (1/3² - 1/4²) = 5.3 * 10^5/m
λ = 1.875 * 10-6 m = 1875 nm
Left: red and white rock with rounded grains and coarse texture. Right: flat, gray rock composed of thin layers.
Which statement about the rocks is accurate?
The rock on the right is foliated.
The rock on the left formed from granite.
The rock on the left is formed from cooled magma.
The rock on the right has randomly arranged grains.
Answer:
The rock on the right is foliated
Explanation:
I took the test
density of a piece of wood that has a measurement of 24 cm3 and 768 g
Answer:
The answer is 32 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 768 g
volume = 24 cm³
We have
[tex]density = \frac{768}{24} \\ [/tex]
We have the final answer as
32 g/cm³Hope this helps you
Answer:
The density of wood is 32 g/cm³.
Explanation:
Given data:
Mass of wood = 768 g
Volume of wood = 24 cm³
Density of wood = ?
Solution:
Density is equal to the mass divided by its volume.
Formula:
d = m/v
d = density
m = mass
v = volume
d = 768 g/ 24 cm³
d = 32 g/cm³
The density of wood is 32 g/cm³.
Un estudiante preparo 200 ml de solución de acetato de potasio (CH3COOH ; Masa molar = 98 g/mol ; Ka CH3COOH = 1,8 x 10-5), disolviendo 3,5 g de ácido, la que denomino "Solución A". Posteriormente preparo otra solución de menor concentración del mismo soluto que denomino "solución B" y para ello tomo un volumen de 5,5 ml de la solución A y agrego agua hasta 70 ml de solución. Señale el pH de solución A y B y, la concentración molar de CH3COO- en la solución b.
Answer:
mirar respuesta abajo
Explanation:
Muy bien. Antes de responder lo que piden en el problema, vamos a calcular la concentración inicial de la solución A:
1) Concentración de la solución A:
En este caso, se sabe que se usaron 3,5 g de la sal, se puede calcular los moles usando el peso molecular y la masa:
n = m/PM (1)
Aplicando tenemos:
n = 3,5 / 98 = 0,0357 moles
Conociendo los moles, podemos calcular la concentración:
M = n/V (2)
Aplicando la formula tenemos:
M = 0.0357 / 0.200 = 0.1785 M
Esta es la concentración del ácido etiquetado como "Solución A".
Ahora podemos ver la concentración de la solución B, para luego calcular las concentraciones molares de los iones en solución y sus respectivos pH.
2) Concentración del ácido en la solución B:
Con la concentración de "A", se puede determinar la concentración de la solución B. Aqui podemos esperar que sea un valor mas bajo, puesto que es una dilución la que estamos haciendo. Por lo tanto.
Si se toma 5.5 mL de la solución A, entonces:
n = 0.1785 * 0.0055 = 0.00098 moles
Con esto, se calcula la nueva concentración:
M = 0.00098 / 0.070 = 0.014 M
Esta es la concentración de la solución B. Ahora para calcular pH y concentraciones de los iones en equilibrio, hay que plantear la reacción acido base en equilibrio. Como es el mismo compuesto, usaremos la misma ecuación.
3) pH de las soluciones A y B:
Planteamos la reacción de equilibrio:
CH₃COO⁻ + H₂O <------> CH₃COOH + OH⁻ Kb
Calculando el Kb, sería asi:
Kb = Kw/Ka
Kb = 1x10⁻¹⁴ / 1.8x10⁻⁵ = 5.56x10⁻¹⁰
Ahora reescribimos la ecuación y hacemos una tabla de equilibrio:
CH₃COO⁻ + H₂O <------> CH₃COOH + OH⁻ Kb = 5.56x10⁻¹⁰
i) 0.1785 x x
eq) 0.1785-x x x
Kb = [OH⁻] [CH₃COOH] / [CH₃COO⁻]
Reemplazando nos queda:
5.56 * 10⁻¹⁰ = x² / (0.1785-x)
Y como Kb es muy pequeño, se asume que el valor de x será también pequeño, asi que podemos redondear la resta a simplemente 0.1785, quedando tan solo:
5.56 * 10⁻¹⁰ = x² / (0.1785)
x² = 5.56*10⁻¹⁰ * 0.1785
x = √9.9246*10⁻¹¹
x = 9.96*10⁻⁶ M
Esta es la concentración de [OH⁻] y [CH₃COO⁻] en la solución A.
Aplicando lo mismo para la solución B (Cambiando solo el dato de concentración) nos queda:
x = √5.56*10⁻¹⁰ * 0.014
x = 2.79x10⁻⁶ M = [OH⁻] = [CH₃COO⁻]Finalmente, para calcular pH, se calcula primero el pOH y luego el pH:
pH = 14 - pOH
pOH = -log[OH⁻]
Para la solución A:
pOH = -log(9.96*10⁻⁶) = 5
pH = 14 - 5
pH = 9En el caso de la solución B:
pOH = -log(2.79*10⁻⁶) = 5.55
pH = 14 - 5.55
pH = 8.45Espero te ayude
What was Wegener's continental drift idea?
Answer: In the early 20th century, Wegener published a paper explaining his theory that the continental landmasses were “drifting” across the Earth, sometimes plowing through oceans and into each other.
Explanation: He called this movement continental drift.
Which non-metal have lustre in the following 1. Iodine 2. Chlorine 3. Carbon 4. Silicon
Answer:
Iodine
Explanation:
I hope this answer will help you
Answer:
silicon. ?
Explanation:
lmk if its right.
A 5 milliliter sample of water has a mass of 5 grams. What is the density of water?
HELP ME PLEASE WILL MARK BRAINLIEST! DUE AT 8PM TODAY1. What is the unit of measure for the graduated cylinder? What is the maximum it can measure? What is the minimum measurement?
2. Look at the smallest division on the graduated cylinder. What amount does the smallest division measure?
3.
What are the units of measure on the plastic cup? What is the maximum amount it can measure? What is the minimum measurement?
Answer:
1. Is fortnite travis scott burger
2. Beetlejuice the second
3. The measurement is 69420
Explanation:
my mom told me
Which type of matter cannot be broken down into simpler substances by a chemical change?
A. an element
B. a mixture
C. a solution
D. a compound
Two or more than two atoms with different physical or chemical properties can not combine together to form an element. An element cannot be broken down into simpler substances by a chemical change. The correct option is option A.
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
Element is the basic unit of any compound and molecule which can not be broken further. Mixture, solution and compound are composed of two or more than two elements which can be further broken down easily.
Therefore, an element cannot be broken down into simpler substances by a chemical change. The correct option is option A.
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4. Fill in the space.
(a) Force is measured in the unit of
(b) A body moves in a circular path due to
(c) A
exerts force on iron, cobalt and nickel.
(d) Every object on the earth has
(e) We are able to write because of
(f) The change in displacement in unit time is
(g) The S.I. unit of velocity is
for
and of acceleration is
Answer:
N
Some sort of pulling force to the center
Magnet
Mass
Gravity
Velocity
m/s and m/s^2
Explanation:
How do I put Chlorofluorocarbons in a sentence?
Answer: Here are some examples
Explanation:
1. In the southern spring, ozone is destroyed above Antarctica, mainly by manufactured compounds called chlorofluorocarbons (CFCs )
2. It is now generally accepted that the loss of stratospheric ozone is caused by chemical reactions initiated by chlorofluorocarbons.
3. Your refrigerator and other home appliances emit Chlorofluorocarbons, or CFCs, as do aerosol spray cans.
Hope this hlps!
Explanation:
To be able to put the chemical term chlorofluorocarbons in a sentence, you must first understand what the chemical species denotes.
We know chlorofluorocarbons are a group of compounds that consists of atoms of chlorine, flourine, and carbon.
Now, here are some sample sentences;
Chlorofluorocarbons are one of the leading causes of ozone depletion in the atmosphere. Most national governments are putting measures in place to check the use of chlorofluorocarbons in industrial manufacturing.If we can innovate a substitute for chlorofluorocarbons, the environment would be safer.If the mass of the reactants in the chemical reaction was 25.3 grams, what was the mass of the products
Answer:
5
Explanation:
5
A student submits the following work on the mass number, but he has made a few mistakes. Select the sentences that are incorrect.
Calculating the mass number for an atom requires that we know the atomic number and the number of protons in the atom’s nucleus. The mass number then gives us the average weight of atoms of a given element. Specifically, these units are calibrated by setting the mass number for carbon-12 as 12 atomic mass units. Neutrons and protons have the same masses. However, as long as the number of protons equals the number of neutrons, the values balance out and we always obtain a whole number for the mass number.
Answer
Calculating the mass number for an atom requires that we know the atomic number and the number of protons in the atom’s nucleus. The mass number then gives us the average weight of atoms of a given element. However, as long as the number of protons equals the number of neutrons, the values balance out and we always obtain a whole number for the mass number.
Explanation:
those 3
the number of moles in 4.5 x 10^24 atoms of oxegen is
Answer:
The answer is 7.48 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 we have
[tex]n = \frac{4.5 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 7.47508...[/tex]
We have the final answer as
7.48 molesHope this helps you
: Question List
Question 9 of 15
Total Points: 1 out of 15
The configuration notation shown is for the the element
?
1s^2 2s^2 2p^6 3s² 3p 4s^1
calcium
magnesium
potassium
sodium
Ernest Rutherford's discovery led to the understanding that atoms consist mostly of empty space with
Answer: With a positively charged nucleus.
Explanation:
A metal object has a density of 2 g/ml. When placed in a graduated cylinder with 500 ml of water, the
water rises to 508 ml. What is the mass of the metal object?
Answer:
The answer is 16 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
density = 2 g/ml
volume = final volume of water - initial volume of water
volume = 508 - 500 = 8 mL
We have
mass = 2 × 8
We have the final answer as
16 gHope this helps you
What solution turns litmus paper red?
A. acidic
B. neutral
C. none
D. basic
Answer:
The answer is A please mark brainliest
Explanation:
What volume will 250. mL of gas at STP occupy ig the pressure changes to 2.0 atmospheres and the temperature changes at 30 degrees Celsius
Answer:
it is 75 degrees
Explanation:
Volume is 138.7 mL.
The equation for calculation of volume is as follows:-
[tex]\frac{P_1V_1}{T_1} =\frac{P_2V_2}{T_2}[/tex]
STP:-
Temperature=273 K
Pressure=1 atm
[tex]\frac{1 atm\times250mL}{273 K} =\frac{2 atm\times V_2}{303\ K}\\V_2=138.7\ mL[/tex]
Hence, the volume is 138.7 mL.
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The number of electrons in the outermost shell of nitrogen atom
Answer:
5
Explanation:
Radio waves are primarily used to
Answer:
Radio is used primarily for communications including voice, data and entertainment media.
How many hydrogen atoms are in 2h2+02—2h20?
Answer: Two hydrogen atoms
Explanation:
A water molecule (formally known as dihydrogen monoxide) is composed of two hydrogen atoms and one oxygen atom. But you can't simply take two hydrogen atoms and stick them onto an oxygen atom. The actual reaction to make water is a bit more complicated: 2H2 + O2 = 2H2O + Energy.
Find the unknown quantity
D=5g/cm to the 3 power
V=?
M=20g
Answer:
The answer is 4 cm³Explanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question
mass = 20 g
density = 5 g/cm³
So we have
[tex]volume = \frac{20}{5} \\ [/tex]
We have the final answer as
4 cm³Hope this helps you
The density of a liquid substance is 0.95 g/mL. Three students calculated the density as 0.56 g/mL. Calculate the percent
error.
Answer:
The answer is 41.05 %Explanation:
The percentage error of a certain measurement can be found by using the formula
[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\ [/tex]
From the question we have
actual number = 0.95 g/mL
error = 0.95 - 0.56 = 0.39
We have
[tex]p(\%) = \frac{0.39}{0.95} \times 100 \\ = 41.0526315...[/tex]
We have the final answer as
41.05 %Hope this helps you
An 8th grade goes to a restaurant for dinner with their family. At dinner, the student orders iced tea. The ice and tea combined to weigh 210 grams. The student then added sugar and lemon to their tea. The sugar weighed 20 grams and the lemon weighed 15 grams. After adding the sugar and lemon, the student stated the tea weighs 225 (210 grams ice & tea + 15 grams lemon) grams since only the lemon would add weight to the tea because the sugar was dissolved. Do you agree or disagree with the statement? Justify your choice.
Answer:
Disagree, the total mass is 245 grams.
Explanation:
We need to keep in mind the Law of Conservation of Mass. Each gram added to the lemonade (a system) will remain there unless it is somehow removed. The added mass of both sugar and lemon count for the total mass (210+20+15), even if the sugar was dissolved.
Please help!
We are doing a lab and I have trouble doing the data analysis. Using my data collection, Can you guys help me using the MC delta T equation?
4.94 x c . (Tm-23.6)=C.(23-6-21.9)+123.13 x c. (23.6-21.9)
Further explanationThe law of conservation of energy can be applied to heat changes, ie the heat received/absorbed is the same as the heat released
Q in = Q out
Heat can be calculated using the formula:
Q = mc∆T
A calorimeter is a device used to measure the specific heat of material
A metal is put into a calorimeter that contains water and there will be heat transfer:
[tex]\tt \displaystyle m_mc_m (T_m-T)=m_wc_w(T-Tw)[/tex]
m = metal
w = water
T = the final temperature of the mixture
mass of metal =(Nickel) = 4.94 g
mass of calorimeter = 12.5 g
mass of water = 123.13 g (135.63 - 12.5)
The equation
Q released (metal) = Q absorbed(calorimeter+water)
Qmetal = 4.94 x c . (Tm-23.60)Q calorimeter = C.(23-6-21.9) --> C = heat capacity of calorimeterQ water = 123.13 x c. (23.6-21.9)The equation :
4.94 x c . (Tm-23.6)=C.(23-6-21.9)+123.13 x c. (23.6-21.9)
Name five elements of the Periodic Table and name three properties for each element listed. For example, Oxygen: polarity.
Fossil evidence sssssssssssssssssssssss
Fossils are essentially clues that have been left behind by various forms of living things. They are instrumental tools for understanding the diverse groups of organisms that have inhabited our planet at one time or another. A fossil is any preserved evidence of an organism.
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A lump of chromium (Cr) has a specific heat of 0.448J/g℃. It is heated to a temperature of 89.5℃ and placed into a calorimeter with 75.2 mL of water at 20.5℃. After stirring, the final temperature of the water, Cr metal, and calorimeter is 27.4℃. What is the mass of Cr metal?
Answer:
Mass of Cr= 78 g
Explanation:
Given data:
Specific heat of Cr = 0.448 j/g.°C
Initial temperature of Cr lump = 89.5°C
Mass of water = 75.2 mL or 75.2 g
Initial temperature of water = 20.5°C
Final temperature of water = 27.4°C
Mass of Cr = ?
Solution:
when we placed the lump of Cr metal into water heat lost by limp is equal to the heat gain by water.
Specific heat capacity of water is 4.184 j/g.°C
Q = mcΔT
Q = 75.2 g× 4.184 j/g.°C × (27.4°C - 20.5°C)
Q = 2171 J
Heat lost by Cr lump is -2171 J. Now we will calculate the mass of Cr.
Q = mcΔT
-2171 J = m ×0.448 j/g.°C × ( 27.4°C- 89.5°C)
-2171 J = m × -27.821 j/g
m = -2171 J/-27.821 j/g
m = 78 g
Which statement desrcribes an intensive property of matter? -it is the same for every sample of a single substance -it depends on how a substance was formed -it is the same for every sample of every substances -it depends on the amount of substances present
Answer:
The statement which describes an intensive property of matter is - :
it is the same for every sample of a single substance.
Explanation:
It is the same for every sample of a single substance. -: Since a substance 's intense property does not depend on either mass or volume, it is the same for each sample of a single substance. Hence , this statement is correct .It depends on how a substance was formed -: Intensive property do not depend upon the amount of the substance or the formation of the sample . Therefore this statement ifs wrong about intensive property .It is the same for every sample of every substances -: This is not possible to be for every sample of the substance , a every substance have different qualities. Hence this statement is also incorrect.it depends on the amount of substances present -: This is the characteristic of a extensive property of matter that relies on the amount of the material/substance. This assertion is, therefore, not valid.Hence , the correct option is A (it is the same for every sample of a single substance).