Answer:
The group number in the periodic table represents number of valence electrons of the elements in a certain group.
Explanation:
There are s, p, d, and f blocks, which you can see in periodic table
The s-block and p-block together are usually considered main-group elements, the d-block corresponds to the transition metals, and the f-block encompasses nearly all of the lanthanides (like lanthanum) and the actinides (like actinium)
There are three main principles, which may useful for you:
The Pauli exclusion rule basically says that at most, 2 electrons are allowed to be in the same orbital. Hund’s rule explains that each orbital in the subshell must be occupied with one single electron first before two electrons can be in the same orbital. The Aufbau process describes the process of adding electron configuration to each individualized element in the periodic table.Hope this helps!
Hello,can you guys please write me an explanation on the question below, the best answer will get brainliest
Answer:
I just umm
Explanation:
Which equation illustrates conservation of mass?
O 1 H2 + 1 O2 + 2 H2O
O 1 H2 + 1 2 + 1 H2O
O 1 H2 + 1 Cl2 +1HCI
O 1 H2 + 1 Cl2 + 2HCI
Answer:
1H₂ + 1Cl₂ → 2HCl
Explanation:
The reaction that illustrates the law of conservation of mass is shown below:
1H₂ + 1Cl₂ → 2HCl
According to the law of conservation of mass "in a chemical reaction, matter is neither created nor destroy but atoms are rearranged".
Therefore, we are expected to the end a reaction with the amount of substance we start with.
Element H Cl
Reactants 2 2
Products 2 2
We see that number of atoms on both sides are the same.
Steel is an alloy of iron and carbon. The addition of carbon to iron enhances which of the following properties of iron metal?
O A hardness
O B. malleability
O C. ductility
O D. softness
Answer:
The answer should be A. Adding carbon to iron makes it tougher and stronger.
The addition of carbon atom to iron metal, enhances the property of hardness of metal.
What is alloy?Alloy is a compound which is formed by the mixture of two or more than two metals with different properties to make a new compound with better properties.
When we add carbon atom in the iron metal, it deviates the crystal lattice property of iron and makes it more harder. So, the content of carbon in the iron is directly proportional to the hardness of iron metal.
Hence, option (A) is correct i.e. hardness.
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what are three things that are considered a chemical change
Answer:
Color change, precipitation, bubbling
Explanation:
Chemical change changes the chemical composition and undergoes a process in which it results as a new substance.
A first order reaction has a rate constant of 0.924 at 25 oC. Given that the activation energy is 89.8 kJ/mol, calculate the rate constant at 33.3 oC.
Answer:
[tex]k_2=2.46[/tex]
Explanation:
Hello!
In this case, according to the Arrhenius equation for variable temperature:
[tex]ln(\frac{k_2}{k_1} )=-\frac{Ea}{R}(\frac{1}{T_2} -\frac{1}{T_1} )[/tex]
Given the temperatures to be computed in kelvins and the activation energy, we obtain:
[tex]ln(\frac{k_2}{0.924} )=-\frac{89800J/mol}{8.314J/(mol*K)}(\frac{1}{306.45K} -\frac{1}{298.15K} )\\\\ln(\frac{k_2}{0.924} )=0.981\\\\k_2=0.924*exp(0.981)\\\\k_2=2.46[/tex]
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what type of boundary is formed when two continental plates converge, buckle and push up into mountain rages?
Answer: Convergent Boundary
Explanation:
Two plates converge at one point
HURRY WHICH ONE IS IT??
Answer:
Protons are positive, electrons are negative, neutrons have to charge. Most of an Atoms mass comes from its protons and neutrons
Explanation:
I took some notes in my notebook about Atoms.
8. Neil pogo sticks from his locker to his science class. He travels 8 m east then 8 m west
back to his locker. What distance did he cover? What was his displacement?
Answer:
12
Explanation:
The distance that Neil Pogo travels is 16 meters. While the displacement is Zero (0).
What is Displacement?Displacement may be defined as the distance traveled by an object from the initial point to the final point. It is a vector quantity and has a direction and magnitude. In a more simple sense, it is known to be the alteration of the position of the object.
According to the question,
The total distance covered by Neil Pogo = 8 m east then 8 m west = 16 meters.
But according to the definition of displacement, his total displacement was zero. This is because the distance between his initial point and the final point is zero.
He returned back to the same place indicating his zero displacements.
Therefore, the distance that Neil Pogo travels is 16 meters. While the displacement is Zero (0).
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Hi pls help me if you know the answer pls ASAP thank you
To determine the freezing point depression of a LiCl solution, Toni adds 0.317 g of LiCl to the sample test tube along with 20.5 mL of distilled water. Determine the concentration, in molality, of the resulting solution. MW of LiCl is 42.394 g/mol Density of H2O is 0.9982 g/mL
Answer:
0.365 m
Explanation:
The definition of molality is:
molality = moles of solute / kg of solventFirst we calculate the moles of the solute, LiCl. We do so using its molar mass:
0.317 g ÷ 42.394 g/mol = 7.48x10⁻³ molThen we calculate the mass of the solvent, water. We do so using its density:
20.5 mL * 0.9982 g/mL = 20.5 g20.5 g / 1000 = 0.0205 kgFinally we calculate the molality of the solution:
7.48x10⁻³ mol / 0.0205 kg = 0.365 mA gas stream contains 18.0 mole% hexane and the remainder nitrogen. The stream flows to a condenser, where its temperature is reduced and some of the hexane is liquefied. The hexane mole fraction in the gas stream leaving the condenser is 0.0500. Liquid hexane condensate is recovered at a rate of 1.50 L/min. N2 C6H14(v) (5.00 mole%) N2 C6H14(v) (18.0 mole%) Liquid condensate 1.50 L C6H14 (l)/min CONDENSER (a) What is the flow rate of the gas stream leaving the condenser in mol/min
Answer:
the flow rate of the gas stream leaving the condenser is 71.9 moles/min
Explanation:
Given the data in the question and the figure below;
N2 BALANCE
(100% - 18%) × ( mole rate in ) = ( 100% - 5%) × ( mole rate out)
0.82 × ( mole rate in ) = 0.95 × ( mole rate out)
mole rate in = 0.95 × ( mole rate out) / 0.82
mole rate in = 1.1585365853 × ( mole rate out)
now;
HEXANE BALANCE
0.18 × ( mole rate in ) = 0.0500 × ( mole rate out) + condensate --- equ 1
but condensate = 1.5 L/min × ( density of hexane ) × 1/molar mass of hexane
we know that;
density of hexane is 0.6548 g/mL
and molar mass of hexane is 86.18 g/mol
so,
condensate = 1.5 L/min × ( 0.6548 g/mL × 1000 mL/L ) × ( 1/86.18 g/mol)
condensate = 11.3970758876
now lets substitute into equation 1
0.18 × ( mole rate in ) = 0.0500 × ( mole rate out) + condensate
⇒ 0.18 × ( 1.1585365853 × ( mole rate out) ) = 0.0500 × ( mole rate out) + 11.3970758876
⇒ 0.208536585354(mole rate out) = 0.0500( mole rate out) + 11.3970758876
⇒ 0.208536585354(mole rate out) - 0.0500( mole rate out) = 11.3970758876
⇒ 0.158536585354(mole rate out) = 11.3970758876
mole rate out = 11.3970758876 / 0.158536585354
mole rate out = 71.889247 ≈ 71.9 moles/min
Therefore, the flow rate of the gas stream leaving the condenser is 71.9 moles/min
Astronomers send probes to other planets to take pictures of their surfaces. An astronomer thinks that briny water flows on Mars because he noticed certain features in one picture of Mars. Which method did the astronomer
use to form this hypothesis?
1.reading scientific literature
2.making careful observations
3. analyzing a natural experiment
4. conducting a controlled experiment
Answer: the answer is B
Explanation:
Examine the diagram of the cell cycle.
Which label identifies the stage in which the DNA is copied and the cell grows?
A-W
B-X
C-Y
D-Z
Explanation:
i think w is the required answer
The diagram below shows part of the rock cycle. (6 points)
Rock cycle with a volcanic eruption at the top. Moving counterclockwise, there is an arrow pointing to Rock B. From Rock B there is an arrow labeled sediment and compaction pointing to Rock C. From Rock C there is an arrow labeled heat and pressure pointing to Rock A. From Rock A there is an arrow labeled magma pointing back to volcanic eruption.
Which type of rock does B represent?
Igneous rock
Metamorphic rock
Rock formed by compaction
Rock formed by heat and pressure
Answer:
Igneous Rock
Explanation:
Assuming this is a cycle, the volcanic eruption would lead back to rock B; rocks formed by volcanic eruptions are considered Igneous.
Answer:
igneous rock
Explanation:
theres this song that i was taught in fourth grade that kind of helped me remember. metamorphic is heat and pressure, sedimentary is erosion and weather, and igneous is cooled magma. rock be is shown after the volcano
Which of the following Noble Gases has only 2 valence electrons because it only has 1 energy level?
Helium (He)
Neon (Ne)
Argon (Ar)
Krypton (Kr)
Answer:
it is he
Explanation:
beacuse Noble gases have 2 volence
A student is measuring the mass of a two metal cylinders. The following data is collected. The actual mass of each cylinder is given. Answer the following questions. Metal Cylinder A 12.4 grams Actual mass of metal cylinder A 12.7 g Metal Cylinder B 75.4 grams Actual mass of metal cylinder B 75.1 g a. What is the absolute error for the measurement of metal cylinders A and B
Answer:
Absolute error in measurement of A = 0.3
Absolute error in measurement of B = 0.3
Explanation:
Absolute error is a measure of the amount of error in a measurement i.e. a measure of how far away a measurement is from a true value or an indication of the uncertainty in a measurement.
The Absolute Error is the difference between the actual and measured value. In formula, the absolute error, Δx is given as:
Δx = |xi – x|,
Where: xi is the measurement, x is the true value,
| | indicates that only absolute values are taken
In the measurements by the student in the question:
Metal Cylinder A
measured value = 12.4 grams
actual mass of metal cylinder A = 12.7 g
Using the absolute error formula; Δx = |xi – x|
Absolute error in measurement of A = |12.4 - 12.7| = 0.3
Metal Cylinder B
measured value = 75.4 grams
actual mass of metal cylinder B = 75.1 g
Using the absolute error formula; Δx = |xi – x|
Absolute error in measurement of B = |75.4 - 75.1| = 0.3
1.A cup of coffee with cream and sugar is a mixture (true or false)
2.give two examples of mixtures you see everyday in life
3.Look at the pictures of methods of separating a mixture and write down the correct names under each picture
(pictures are attached)
How to calculate the orbital period of earth
Answer:
By observing the time between transits, we know the orbital period. Kepler's Third law can be used to determine the orbital radius of the planet if the mass of the orbiting star is known (R3=T2−Mstar/Msun, the radius is in AU and the period is in earth years)
hope this helps you out
ANSWER ASAP
2. The figure shows the first three rows, or periods, of the periodic table. Suppose the fourth period is added. How many orbits will the Bohr models in the fourth period have? How many electrons will an atom in Group 1 in the fourth period have?
Answer:
19 electrons in first group of 4th period element that is potassium K
Explanation:
Name the following lonic Compounds using the lonic naming rules. Remember, place the metal's name
first, followed by the non-metal element, replacing the ending with "-ide"
1.Caci,
2.LIBr
I
3. Bes
4. LIF
5. K Se
6. Sr,P2
7. Baci
8. Feo
9. Fe,
10. CUN
11. Cun,
Please help meeee
What is the mass of 2.90 L of O2 gas at STP
Answer:
4.16 g
Explanation:
Volume, V = 2.90 L
STP mans standard temperature and pressure
T = 273 K
P = 1 atm
Mass = ?
Using the ideal gas equation;
PV = nRT
where R = General gas constant = 0.082 L atm mol-1 K-1
n = PV / RT
n = 1 * 2.90 / (0.082 * 273)
n = 2.90 / 22.386
n = 0.130 mol
The relationship between moles and mass;
Mass = number of moles * Molar mass
Mass = 0.130 mol * 32 g/mol
Mass = 4.16 g
Answer:4.14
Explanation:just answered the question
Which source of electricity would harm the environment the least?
Answer: Wind energy.
Explanation: Wind energy is the least harmful form of energy because unlike coal. It doesn't leave a big footprint. Although, to this date every form of energy still has a footprint, it just might not be big.
__Fe + ___ Cl2 --> ___FeCl3
The coefficient on iron for this equation is:
A 4
B 2
C 1
D 3
If a substance has a density of 2.545g / mL how many grams would the substance weigh if the sample has a volume of 122.1 mL?
Answer: 310.7 grams
Explanation:
Multiply the two values so the units of mL cancel and you get grams
2.545*122.1 = 310.7 grams
What is the mass of 5.35 moles of potassium phosphate
Explanation:
given
kpo4 it has molar mass of 39+31+(16*4)=134
m=n*Mm
m=5.35*134
m=716.9
the atomic number of potassium is 19. How many electrons does this element have?
Answer:
Potassium is an element that has 19 electrons
I’ll give you a lot of points and mark you brainlist if you awnse all 3
Answer:
Magma
Volcanic glass
Granite and pumice
Explanation:
Answer:
Magma,
Volcanic Glass,
Granite and Pumice,
Lava
Explanation:
How many grams in 3 moles of H2O?
How many miles in 519.3g FeCl3?
How many grams in 2 moles of Co?
Answer:
There are 54.03 grams in 3 moles of H2O
There are 3.2 moles in 519.3 g FeCl3
There are 56.0 g in 2 moles of CO
Explanation:
H2O molar mass: 18.01 g/mol
to calculate the grams: 3 mol H2O * 18.01 g/mol
FeCl3 molar mass: 162.2 g/mol
to calculate moles: 519.3g FeCl3 / 162.2 g/mol
CO molar mass: 28.01 g/mol
to calculate grams: 28.01 g/mol CO * 2 mol CO
Describe the motion of a person NOT wearing a seat belt if the car stops suddenly
A the person and car will stop together
B the person will stop faster than the car because they are lighter
C the car will stop and the person will keep moving forward
D the car will stop and the person will speed up
Answer:
c the car will stop and the person will keep moving forward
Explanation:
Because since the person has no force apllied they will keep moving until force is apllied.
2. The boiling point of a solution containing 6.4 g of the hormone adrenaline in 360 g of
CCl4 is 0.49 K higher than the boiling point of pure CC14. Calculate the molar mass of
adrenaline. (K = 5.02 kg K/mol).
Answer:
MM = 182.13g/mol
Explanation:
Hello!
In this case, since the boiling point elevation is computed via:
[tex]\Delta Tb=i*m*K[/tex]
Thus, since adrenaline is nonionizing, we can compute the molality at first instance:
[tex]m=\frac{\Delta Tb}{i*K}=\frac{0.49K}{1*5.02kg\frac{K}{mol} } \\\\m=0.0976mol/kg[/tex]
Now, we compute the the moles of adrenaline in 360 g (0.360 kg) of CCl4:
[tex]n=0.0976mol/kg*0.360kg\\\\n=0.0351mol[/tex]
Finally, the molar mass:
[tex]MM=\frac{6.4g}{0.0351mol}\\\\MM=182.13g/mol[/tex]
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