Answer:
Globular clusters are densely packed collections of ancient stars. Roughly spherical in shape, they contain hundreds of thousands, and sometimes millions, of stars. Studying them helps astronomers estimate the age of the universe or figure out where the center of a galaxy lies.
Explanation:
The diagram below represents the bone
arrangements in the front limbs of three different
species of mammals.
The similarities and differences in these limbs
suggest that all three species developed from the
same ancestor, but
Answer:
these species share a common ancestor
Explanation:
What is the theoretical oxygen demand in liters of air for a 50 mg / L acetone solution, CH3COCH3, to decompose completely?
Answer:
18.368 Liters
Explanation:
Given that balanced Acetone oxidation,
= C3H6O + 4O2 = 3CO2 + 3H2O
lets assume volume of acetone = 1 liter
mass of acetone = 50 mg
number of moles present = (5*10^-3)g / ( 58.08 ) = 0.0000861 mol
Given that : I mol of ( acetone ) = 4 mol of oxygen
∴0.0000861 mol of acetone = 0.0003444 mol of oxygen
also note that the ratio of air to oxygen is
0.21 mol of oxygen = 1 mol of air
∴ 0.0003444 mol of oxygen = 0.00164 mol of air (0.0003444 / 0.21 )
note : 1 mol at STP = 22.4 L (at STP = Temperature = O°C
Finally the theoretically oxygen demand in liters of air for a 50 mg/L of acetone to decompose
Given that Acetone decompose/degrade completely between 500°C - 600°
we will take 500° for the sake of this calculation
The oxygen demand in liters will be
= 22.4 * 0.00164 * 500 = 18.368 Liters
The theoretical oxygen demand in liters of air for a 50 mg / L acetone solution, to decompose completely is 18.368 Liters.
How we calculate moles?Moles of any substance will be calculated as:
n = W/M, where
W = given mass
M = molar mass
Given chemical reaction is:
CH₃COCH₃ + 4O₂ → 3CO₂ + 3H₂O
Given mass of acetone = 50mg = 0.05g
Moles of acetone = 0.05g / 58.08g/mol = 0.0000861 mole
From the stoichiometry of the reaction, it is clear that:
1 mole of CH₃COCH₃ = 4 moles of O₂
0.0000861 mole of CH₃COCH₃ = 4×0.0000861=0.0003444 moles of O₂
We know that ratio of air is:
0.21 mole of oxygen present = in 1 mole of air
0.0003444 mole of oxygen present = in 0.0003444/0.21=0.00164 mole of air
At STP 1 mole of gas is present in 22.4 Liter.
Degradation of acetone takes place in 500°C - 600°C.
Theoretical oxygen demand = 22.4×0.00164×500 = 18.368 Liters
Hence, theoretical oxygen demand is 18.368 Liters.
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A generator can produce both _______________________ (DC), which flows in one direction,and AC current;large power plants produce ___________________.
Answer:
1. direct current. 2. electrical power
Explanation
i believe number 2 is right
Can a molecular formula ever be the same as an empirical formula? Explain your answer.
Answer:
The molecular formula for a compound can be the same as or a multiple of the compound's empirical formula. Molecular formulas are compact and easy to communicate; however, they lack the information about bonding and atomic arrangement that is provided in a structural formula.
Explanation:
Answer: Hello Luv......
Hope this helps. Please mark me brainest... Anna ♥
Explanation:
The molecular formula for a compound can be the same as or a multiple of the compound's empirical formula. Molecular formulas are compact and easy to communicate; however, they lack the information about bonding and atomic arrangement that is provided in a structural formula.
What type of bond would be formed between nitrogen (N) and nitrogen (N)? Why?
an ionic bond because there is less than a 0.4 difference in electronegativity between the atoms
a polar covalent bond because there is less than a 0.4 difference in electronegativity between the atoms
a nonpolar covalent bond because there is less than a 0.4 difference in electronegativity between the atoms
Answer: The compound formed between nitrogen (N) and nitrogen (N) a polar covalent bond because there is less than a 0.4 difference in electronegativity between the atoms.
Explanation:
If electronegativity difference between two atoms is less than 0.4 then bond formed is a pure covalent bond.
If electronegativity difference between two atoms is between 0.4 to 1.8 then bond formed is a polar covalent bond.
If electronegativity difference between two atoms is greater than 1.8 then bond formed is an ionic bond.
The electronegativity value of a nitrogen atom is 3.04. Hence, the electronegativity difference of [tex]N_{2}[/tex] molecule is as follows.
[tex]Electronegativity difference = electronegativity value of N - electronegativity value of N\\= 3.04 - 3.04\\= 0[/tex]As the electronegativity difference is 0 which is less than 0.4.
Hence, we can conclude that the compound formed between nitrogen (N) and nitrogen (N) a polar covalent bond because there is less than a 0.4 difference in electronegativity between the atoms.
in which type of condition is a conditions is a landslide most likely to occur
Answer:
B. In a wet, hilly area
Explanation:
We know that for a landslide to happen, there has to be a down hill slope so it can fall.
This eliminates answers C, D and E.
So we are left with A and B
Now we can look at this in a real life scenario. If you have ever walking on wet ground, you will know that is weaker than dry ground. Knowing this, we know the answer will have to be answer B.
Please answer all of the examples below!
Answer:
The first one is balanced. The second one is not.
Explanation:
The first one is balanced because there are the same amount of elements on the reactant side as there are on the product side. The second one is not balanced because there are not the same amount of elements on the reactant side as there are on the product side. Therefore, it is not balanced
More Detailed: first example
Reactant side (left of arrow)
H: 2
C: 1
O: 3
Product side (right of arrow)
H: 2
C: 1
O: 3
More detailed: second example
Reactant side:
Na: 1
O: 1
H: 1
C: 1
Product side:
Na: 2
O: 4
H: 2
C: 1
the variables needed to balance this equation is 2,1, 1, 1.
What is a subcript? Give an example.
Answer:
subscript is a character
Explanation:
A subscript is a character (such as a number or letter) that is set slightly below or above the normal line of type, respectively. It is usually smaller than the rest of the text.
PLS HELP
A 20.8 gram piece of metal at 184.9 oC is dropped into 87.7 grams of water at 19.2 oC. The water temperature rose to 54.6 oC. Calculate the specific heat of metal in J/g oC. (round to the tenths place) (DO NOT PUT UNITS IN YOUR ANSWER.)
Assume that all of the heat lost by the metal is transferred to the water and no heat is lost to the surroundings. The specific heat of water is 4.184 J / g oC.
Answer:
Explanation:
A 12.48 g sample of an unknown metal, heated to 99.0 °C was then plunged into 50.0 mL of 25.0 °C water. The temperature of the water rose to 28.1 Go to calculating final temperature when mixing two samples of water ... Problem #1: A 610. g piece of copper tubing is heated to 95.3 °C and placed in an ... The two rings are heated to 65.4 °C and dropped into 12.4 mL of water at 22.3 °C. ... Problem #4: A 5.00 g sample of aluminum (specific heat capacity = 0.89 J g¯1
formula of velocity rate
Answer:
V=d/t
,,,,,,,,,,,,,,,,,
What volume in liters will 50.0g CO occupy? please show work.
Answer:
40.0L is the volume the CO occupy
Explanation:
To solve this question we must assume the gas is at STP. To find the volume of a gas using the moles, temperature and pressure of the gas we have to use:
PV = nRT
V = nRT / P
Where V is volume in liters
n are moles of the gas -Molar mass CO: 28g/mol-
50.0g * (1mol / 28g) = 1.786 moles CO
R is gas constant = 0.082atmL/molK
T is absolute temperature = 273.15K at STP
P is pressure = 1atm at STP
Replacing:
V = 1.786moles*0.082atmL/molK*273.15K / 1atm
V = 40.0L is the volume the CO occupy
Wat two common uses for Zinc???
Answer:
Zinc oxide is used in the manufacture of many products such as paints, rubber, cosmetics, pharmaceuticals, plastics, inks, soaps, batteries, textiles and electrical equipment.
Explanation:
* Describe the structure and behavior of the inner Earth
Answer:
The interior of the Earth, like that of the other terrestrial planets, is chemically divided into layers. The Earth has an outer silicate solid crust, a highly viscous mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core.
Ca(NO3)2 wht is the mass
Answer:
164.088 g/mol
Explanation: hope this helps
Answer:
Calcium nitrate
Explanation:
164.088 g/mol
give me the brainliest plss
Which of these is the BEST definition of "civilization" for a history class? A) the way people talk B) a group that has a culture C) the ability to walk upright D) how sophisticated people behave
Answer:
Is C
Explanation:
Somebody look at all the science questions i posted plzzz help ( i will give brainliest
Answer:
ok
Explanation:
The Balanced equation for the combustion of ethene is given below. If 97.7 g of oxygen is used, how much heat energy will be produced?
Answer:
the answer is d. 74.02
Explanation:
When ogyen all together with the different things to get this.
. What is the molarity of 5.30 moles of NaCl dissolved in 0.400 L of solution?
Answer:
13.25 M
Explanation:
Molarity is moles over liters so simply plug your values in as such:
5.30 mol ÷ 0.400 L = 13.25 M
Hydroelectric requires this force to increase the mechanical energy gathered.
Combustive
Velocity
Gravitational
Thermal
Perform the following operation and express the answer in scientific notation. 7.0x10^3 x 1.1x10^7
Answer:
The answer is 7.7 ×10¹⁰
Explanation:
7.0 × 10³ × 1.1 × 10⁷
7.7 ×10¹⁰
Thus, The answer is 7.7 ×10¹⁰
-TheUnknownScientist
How many formula units are there in 7.55 moles potassium chloride?
Answer:
mole is equal to 1 moles Potassium Chloride, or 74.5513 grams.
What are the products of the following neutralization reaction? (No need to balance)
H3PO4 + Ba(OH)2 --> ??? + ???
A.)H2O + Ba3(PO4)2
B.)H30+ + BaPO4
C.)H30+ + Ba3(PO4)2
D.)H2O + BaPO4
H3PO4 + Ba(OH)2 --> Ba3(PO4)2 + H2O
so, (A) H2O + Ba3(PO4)2 is your answer.
Lightning is caused by the build-up of and subsequent striking of electrons against the ground. Is a lightning bolt striking the ground an example of potential or kinetic energy?
Answer:
Kinetic
Explanation:
C=C + H-H —> C-H + C-H
Answer:
What is that supose to mean?
Answer:
I would never think that would be even a real question....what does it mean? what math problem is this?! I've never seen this in my life...does it mean... CCHHCHCH? *laughs nervously*
Explanation:
Have a Blessed Day.
HELP!!! WILL MARK BRAINLIEST!!!
picture attached below
Answer:
0.2 cm
Explanation:
looking at the ruler, you can see that the diameter is 0.4 cm. to get the radius, just divide by two, which gets 0.2 cm as the radius
Pls answer I am giving lots of points and need all the work shown. Determine the kb for chloroform when 0.793 moles of solute in 0.758 kg changes the boiling point by 3.80 °C.
Answer:0.87
Explanation:
pls help help help!
i give 20 points
pls
Answer:
His name is Harold
Explanation:
please help!!
i’m trying to go to sleep
Answer:
4) C
6) true
I am not sure about 5th one
4) evaporation rate
5) acetone
6) true
How can genetic mutations be passed to offspring?
A. In sex cells
B. In body cells
C. Through environmental factors
D. Through animal transmission factors
Answer:
I think the answer is b
Explanation:
I hope this helps
An element has the atomic number 72. The number of protons and electrons in a neutral atom of this element is
Explanation:
Hi,
The number of protons is equal to the atomic number. The number of electrons in a neutral atom is equal to the number of protons. So, in this case, you have 72 protons and 72 electrons.
I hope this helps :)
If an element has the atomic number 72, then the number of protons is also equal to 72. As it is clearly mentioned in the question that it is a neutral atom, which means the number of protons is equal to the number of electrons which is also 72.
What is meant by an Atomic number?An atomic number may be defined as the number of a chemical element in the modern periodic table through which the elements are systematically arranged in order of increasing the number of protons in the nucleus.
According to the context of this question, the atomic number of every element is always equal to the number of protons it has. While in a neutral atom, the number of electrons is equal to the number of protons. For calculating the number of neutrons, you have to subtract the atomic number from the atomic mass.
Therefore, there are 72 protons of an element whose atomic number is 72. The number of electrons is also 72.
To learn more about Atomic numbers, refer to the link:
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