Answer:
c
Explanation:
ok than not c than b maybe
(will give brainliest!! please help me! thank you!)
a) The rows on the periodic table are called periods. How many energy levels are in the atoms of each element in period 2 (lithium-neon)
b) What is the group number of the halogens?
c) What do the elements in each group have in common?
please please help me, i will give brainliest
Answer:
A two energy levels K and L
B halogen are present in group 17
C in same group elements have same valence electrons
Explanation:
In the Energy and Specific Heat lab, what temperature should be recorded as the final temperature of the water when measuring the food sample?
A. The temperature of the water when the food sample is first lit
B. The temperature of the water when the food sample has finished burning completely.
C. The highest temperature the water reaches as the sample burns
D. The temperature of the water after the food sample ash has been removed
Answer:
B. The temperature of the water when the food sample has finished burning completely.
Explanation:
Heat or thermal energy is a form of energy that transfers from one object to another due to a temperature difference between the objects. The units for heat are joules or calories.
Calorimetry is the measurement of heat energy released or absorbed in a chemical reaction. A calorimeter is used in calorimetry. The calorimeter operates on the Law of Conservation of Energy which states that energy is never created or destroyed but is transformed from one form to another or between objects.
In food calorimetry, the energy released when food is burned is measured by recording the rise in temperature of water in a calorimeter when a given mass of a food sample is burned completely.
Energy can be calculated using the formula: Q = mc ∆T
where Q = the energy in joules or calories, m = the mass in grams, c = specific heat and ∆T = the change in temperature (final temperature - initial temperature).
The temperature of the water when the food sample has finished burning completely is taken as the final temperature of the water. The sample is allowed to smolder for sometime before recording the final water temperature. This is because the water temperature will continue to rise after the flame has gone out.
Many compressed gases come in large, heavy metal cylinders that are so bevy that they need a special cart to move them around. An 80.0-L tank of nitrogen gas pressurized to 172 arm atm is left in the sun and heats from its normal temperature of 20.0 degrees Celsius to 140.0 degrees Celsius. Determine (a) the final pressure inside the tank and (b) the work, heat, and delta U of the process. assume that behavior is ideal and the heat capacity of diatomic nitrogen is 21.0 j/molk.
Answer:
a) final pressure inside the tank is 242.4 atm
b)
Work = 0
heat q = 1440.85 kJ
DU = 1440.85 kJ
Explanation:
Given that;
Pressure P1 = 172 atm
Volume V = 80 L
Temperature T1 = 20°C = ( 273.15 + 20) = 293.15 K
Temperature T2 = 140°C = ( 273.15 + 140) = 413.15 K
we know that, gas constant R = 0.0821 atm.L/mol.K
from the Ideal Gas equation;
pV = nRT1
n = pV/RT1
we substitute
n = (172 × 80) / (0.0821 × 293.15)
n = 13760 / 24.067615
n = 571.72 moles
now
P2 = nRT2/V2
P2 = (571.72 × 0.0821 × 413.15) / 80
P2 = 19392.5222 / 80
P2 = 242.4 atm
Therefore, final pressure inside the tank is 242.4 atm
b)
we know
w = -∫[tex]P_{ext}[/tex] dv
now, since there is no change in volume; dv = 0
so
w = 0
Work = 0
dU = cVDT
Cv = nCr,m
Cv = 571.72 × 21.0
Cv = 12007.12 J/k
DU = CvΔT
DU = 12007.12 × (413.15 - 293.15)
DU = 1440854.4 J
DU = 1440.85 kJ
DU = q + w
1440.85 = q + 0
heat q = 1440.85 kJ
Joaquin tells his science class that galaxies consist of gas, dust, and many planets. What is the most important component of galaxios Joaquin is missing in his description?
astero de
comets
constellations
Stars
Answer:
the answer is asteroids!
Explanation:
Answer:
astroid
Explanation:
becaus
ASAP I WILL GIVE BRAINLIEST The diagram shows a lever. What is the mechanical advantage of the lever? O 2 03 3 m 6 m mi 0 9
Answer:
A) 2
Explanation:
Answer:
2, i got it right thanks to the other user :) <3
Explanation:
What role do wolves play in the tundra?
Answer:
predator
Explanation:
Wolves, arctic foxes, and snowy owls are predators in the tundra.
How many moles of phosphoric acid would be needed to produce 15 grams of water?
Moles of phosphoric acid would be needed : 0.833
Further explanationGiven
15 grams of water
Required
moles of phosphoric acid
Solution
Reaction(decomposition) :
H3PO4 -> H2O + HPO3
mol water (H2O :
= mass : MW
= 15 g : 18 g/mol
= 0.833
From the equation, mol ratio H3PO4 = mol H2O = 1 : 1, so mol H3PO4 = 0.833
identified the nucleus that is found in an item that has a stable valance electron configuration
Answer:
Nucleus 3 i believe
Today, ammonia is synthesized through a series of reactions (called the Haber-Bosch process) that take place between methane, air (which is four parts N2, one part O2), and potassium carbonate:
7 CH4(g) + 8 N2(g) +2 O2(g) + 17 H2O(g) + 7 K2CO3(s) ?? 16 NH3(g) + 14 KHCO3(s)
What is the equilibrium expression for the Harber-Bosch process?
Answer:
K = [NH₃]¹⁶ [KHCO₃]¹⁴ / [CH₄]⁷ [N₂]⁸ [O₂]² [H₂O]¹⁷ [K₂CO₃]⁷
Explanation:
The equation for the reaction is given below:
7CH₄(g) + 8N₂(g) +2O₂(g) + 17H₂O(g) + 7K₂CO₃(s) —> 16NH₃(g) + 14KHCO₃(s)
Equilibrium constant (K) =..?
Equilibrium constant, K for a reaction is simply defined as the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient.
Thus, the equilibrium expression for the Harber-Bosch process for the synthesis of ammonia can be written as shown below:
K = [NH₃]¹⁶ [KHCO₃]¹⁴ / [CH₄]⁷ [N₂]⁸ [O₂]² [H₂O]¹⁷ [K₂CO₃]⁷
Uranus has a force of Gravity of 8.87 m/s^2. Sam has a MASS of 85 kg. What is his weight in Uranus? *
Answer:
Explanation:
Weight = mass x gravity
mass given = 85 kg
gravity = 8.87 m /s²
Weight = 85 x 8.87 = 753.95 N .
Weight on Uranus = 753.95 N .
Calculate how much heat is absorbed by a sample that weighs 12 kilograms, has a specific heat of 0.231 kg/CJ, and is heated from 45 K to 80 K.
PLEASE ANSWER 20 POINTS
Answer:
97 J
Explanation:
Step 1: Given data
Mass of the sample (m): 12 kgSpecific heat capacity (c): 0.231 J/kg.°C (this can also be expressed as 0.231 J/kg.K)Initial temperature: 45 KFinal temperature: 80 KStep 2: Calculate the temperature change
ΔT = 80 K - 45 K = 35 K
Step 3: Calculate the heat required (Q)
We will use the following expression.
Q = c × m × ΔT
Q = 0.231 J/kg.K × 12 kg × 35 K = 97 J
The reaction that occurs in a Breathalyzer, a device used to determine the alcohol level in a person's bloodstream, is given below. If the rate of appearance of Cr2(SO4)3 is 1.24 mol/min at a particular moment, what is the rate of disappearance of C2H6O at that moment
Answer:
The rate of disappearance of C₂H₆O = 2.46 mol/min
Explanation:
The equation of the reaction is given below:
2 K₂Cr₂O₇ + 8 H₂SO₄ + 3 C₂H₆O → 2 Cr₂(SO₄)₃ + 2 K₂SO₄ + 11 H₂O
From the equation of the reaction, 3 moles of C₂H₆O is used when 2 moles of Cr₂(SO₄)₃ are produced, therefore, the mole ratio of C₂H₆O to Cr₂(SO₄)₃ is 3:2.
The rate of appearance of Cr₂(SO₄)₃ in that particular moment is given 1.64 mol/min. This would than means that C₂H₆O must be used up at a rate which is approximately equal to their mole ratios. Thus, the rate of of the disappearance of C₂H₆O can be calculated from the mole ratio of Cr₂(SO₄)₃ and C₂H₆O.
Rate of disappearance of C₂H₆O = 1.64 mol/min of Cr₂(SO₄)₃ * 3 moles of C₂H₆O / 2 moles of Cr₂(SO₄)₃
Rate of disappearance of C₂H₆O = 2.46 mol/min of C₂H₆O
Therefore, the rate of disappearance of C₂H₆O = 2.46 mol/min
What is the charge is the ion when lithium reacts with chlorine
The number of atoms in 10. grams of calcium is equal to 6.0 x 1023 multiplied by which number?
Answer:
1.51×10²³ atoms.
Explanation:
From the question given above, the following data were obtained:
Mass of Calcium (Ca = 10 g
Number of atom of Calcium (Ca) =?
The number of atoms present in 10 g of Ca be obtained as follow:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This implies that 1 mole Ca contains 6.02×10²³ atoms.
1 mole of Ca = 40 g.
Now, if 40 g of Ca contains 6.02×10²³ atoms.
Therefore, 10 g of Ca will contain = (10 × 6.02×10²³) / 40 = 1.51×10²³ atoms.
Thus, 10 g of calcium contains 1.51×10²³ atoms.
What is aspartame? EXPLAIN
Answer:
it's an artificial non-saccharide sweetener 200 times sweeter than sucrose, and is commonly used as a sugar substitute in foods and beverages. it's a methyl ester of the aspartic acid/phenylalanine dipeptide with the trade names NutraSweet, Equal, and Canderel
Explanation:
Answer:
Aspartame is some type of very sweet substance that is used as an artificial sweetener, and chiefly in low-calorie products. It is a derivative of aspartic acid and phenylalanine.
Explanation:
g Aqueous hydrobromic acid will react with solid sodium hydroxide to produce aqueous sodium bromide and liquid water . Suppose 57.4 g of hydrobromic acid is mixed with 41. g of sodium hydroxide. Calculate the minimum mass of hydrobromic acid that could be left over by the chemical reaction. Be sure your answer has the correct number of significant digits.
Answer:
Zero
Explanation:
The complete reaction for this is as follows -
HBr + NaOH = NaBr + H2O
1 mole of NaOH reacts with 1 mole of HBr
m(HBr) = 57.4g and M(HBr) = 80.9g/mol
m(NaOH) = 16g and M(NaOH) = 40g/mol
Number of moles = m/M
Substituting the given values we get -
n(HBr) = 57.4 g/80.9 g/mol = 0.709
n(NaOH) = 16 g/40 g/mol = 0.4
n(H2O) = n(NaOH) = 0.40 mol
According to balanced equation
40 gram of NaOH reacts with 81 grams of HBr
41 gram of NaOH will react with 81/40 * 41 = 83.025 gram of HBr
We have only 57.4 g of HBr only hence, 0 HBr will be left.
Ivy has a mixture salt and sand . She wants to separate the two substances by pouring the mixture into a jar of water . How could ivy speed up the separation of the two substance? Shake the jar , put the jar into the freezer, add a third substance such as soil to the jar , remove some of the water from the jar before adding the mixture
Answer:
Remove some water from the jar before adding the mixture.
Explanation:
She will speed it up when removing some water it will stay dry and not be sticky to separate the two ingredients
Answer: Remove a bit of water from the jar
Explanation:
a dragster in a race accelerated from rest to 60 m/s by the time it reached the finish line. the dragster moved the distance from start to finish in 8.3 seconds. what is the dragsters acceleration?
i’ll mark brainliest!!
Answer:
7.23m/s²
Explanation:
Given parameters:
Initial velocity = 0m/s
Final velocity = 60m/s
Time taken = 8.3s
Unknown:
Acceleration of the dragsters = ?
Solution:
Acceleration is defined as the rate of change of velocity with time taken.
So;
Acceleration = [tex]\frac{Final velocity - Initial velocity }{time}[/tex]
Acceleration = [tex]\frac{60 - 0}{8.3 }[/tex] = 7.23m/s²
6. 7. A hyperbaric chamber has a volume of 200. L. (a) How many moles of oxygen are needed to fill the chamber at room temperature (23°C) and 3.00 atm pressure? b) How many grams of oxygen are needed? (Hint: Since moles have been asked, which equation has the moles listed in the equation. Use that to solve this problem. Also don’t forget to use the equation 1 mole = Formula weight or Molecular weight to calculate the grams of O2).
Answer:
a) 24.7 mol
b) 790 g
Explanation:
Step 1: Given data
Volume of the chamber (V): 200. LRoom temperature (T): 23 °CPressure of the gas (P): 3.00 atmStep 2: Convert "T" to Kelvin
We will use the following expression.
K = °C + 273.15
K = 23°C + 273.15 = 296 K
Step 3: Calculate the moles (n) of oxygen
We will use the ideal gas equation.
P × V = n × R × T
n = P × V/R × T
n = 3.00 atm × 200. L/(0.0821 atm.L/mol.K) × 296 K = 24.7 mol
Step 4: Calculate the mass (m) corresponding to 24.7 moles of oxygen
The molar mass (M) of oxygen ga sis 32.00 g/mol. We will calculate the mass of oxygen using the following expression.
m = n × M
m = 24.7 mol × 32.00 g/mol = 790 g
Riboflavin is one of the B vitamins It is also known as B6 and is made up of carbon, hydrogen, nitrogen and oxygen atoms. When 10.0 g of vitamin B6 is burned in oxygen, 19.88 g of CO2 and 4.79 g of H2O are obtained. Another experiment shows that vitamin B6 is made up of 14.89% of N. What is the simplest formula for vitamin B6
Answer:
C₁₇H₂₀N₄O₆
Explanation:
First, we need to determine the percentage of the atoms in the molecule. Then, assuming a basis of 100 we must convert the mass of each atom to moles. Simplest formula is the simplest ratio of atoms presents in the molecule:
%C:
19.88g CO2 * (12.01g/mol C / 44.01g/mol CO2) = 5.425g C
5.425g C / 10.0g * 100 = 54.25% C
%H:
4.79g H2O * (2*1.01g/mol / 18.015g/mol) = 0.537g H
0.537g H / 10.0g * 100 = 5.37%
%N:
14.89%
%O:
100 - 14.89% - 54.25% - 5.37% = 25.49%
Moles of each atom in a basis of 100g:
C: 54.25g * (1mol / 12.01g) = 4.517moles
H: 5.37g * (1mol / 1.01g) = 5.317 moles
N: 14.89g * (1mol / 14.01g) = 1.063 moles
O: 25.49g * (1mol / 16g) = 1.593 moles
Dividing each amount of moles in the lower number of moles (moles N):
C = 4.517mol / 1.063mol = 4.25
H = 5.317mol / 1.063mol = 5
N = 1.063mol / 1.063mol = 1
O = 1.593mol / 1.063mol = 1.5
This ratio multiplied 4 times to obtain whole-numbers:
C = 4.25*4 = 17
H = 5*4 = 20
N = 1*4 = 4
O = 1.5*4 = 6
The simplest formula for vitamin B6 is:
C₁₇H₂₀N₄O₆Which of the following choices is not evidence supporting the theory of plate tectonics?
Answer:
B
Explanation:
A student performs an experiment to determine the molar mass of magnesium oxide. The student repeats the experiment five times and collects the following data: 40.220gmol, 40.654gmol, 40.314 gmol, 40.165 gmol, and 40.554 gmol. If the accepted value for the molar mass is 40.304 gmol, what is the percent relative error for the average of this data?
Answer:
Percent relative error = 0.191%
Explanation:
Relative error is a measure of accuracy (How closeness is the measure to the accepted value) for a determined data. The formula is:
Percent relative error = |Experimental - Accepted| / Accepted * 100
Where experimental is the average of the data:
(40.220g/mol + 40.654g/mol + 40.314g/mol + 40.165g/mol + 40.554g/mol) / 5 =
40.381g/mol
Replacing using accepted value = 40.304g/mol:
|40.381g/mol - 40.304g/mol| / 40.304g/mol * 100
Percent relative error = 0.191%Write a description of how you know a chemical reaction is occurring.
ANSWER FAST FIRST PERSON GETS BRAINLIEST
Answer:
See explanation
Explanation:
Chemical reactions are also referred to as chemical change. A chemical change often leads to the formation of new substances and is not easily reversible.
A chemical reaction may be accompanied by the emission of heat and light, formation of a precipitate, evolution of gas, or a color change.
These observable physical effects may tell us weather a chemical reaction has taken place or not so we have to observe the system closely for any of these effects stated above.
I need your help please thank you so much?!?!?
Answer:
The end products cannot be changed back in their original forms
Explanation:
Answer:
the first one
Explanation:
A purified protein is in a HEPES buffer at pH 7.0 with 600 mM NaCl. A 1 mL sample of the protein solution is dialyzed against 1.0 L of the same HEPES buffer with 0 mM NaCl. Once the dialysis has come to equilibrium, what is the concentration (in mM) of NaCl in the protein sample
Answer:
Explanation:
Using the dilution formula to determine the final concentration of NaCl in the protein sample.
[tex]M_1V_1 = M_2V_2[/tex]
[tex]600 \ mM \times 1 \ mL= M_2 \times ( 1000\ mL + 1 \ mL)[/tex]
[tex]M_2= \dfrac{600 \ mM \times 1 \ mL}{ ( 1001\ mL)}[/tex]
[tex]M_2= 0.599 \ mM[/tex]
However, when dialysis attains equilibrium, it implies that the sample was dialyzed twice, SO:
[tex]M_2 = \dfrac{600 \ mM\times 1 \ mL}{201 \ mL} = 2.97 \ mM[/tex]
Now, take the concentration as 2.97 mM
Then:
[tex]M_f = \dfrac{2.985 mM \times 1 mL}{201 \ mL}[/tex]
[tex]M_f = 0.01485 \ mM[/tex]
[NaCl] = 0.01485 mM
What best describes how the processes of scientific
investigation and technological design are involved in
this situation?
O The clothing company conducted a scientific
investigation to communicate results to researchers,
who then used the knowledge in a technological
design.
O The clothing company conducted a scientific
investigation to produce a product that researchers
could then test while designing new technology.
O The clothing company used technological design to
create a product that helped aid researchers
conducting a scientific investigation.
O The clothing company designed a new technology
that provided information researchers needed in order
to continue with their scientific investigation.
Answer:
O The clothing company conducted a scientific investigation to communicate results to researchers, who then used the knowledge in a technological
design.
Explanation:
The products of scientific investigation are converted into technology for use engineers.
Engineering is the application of science to solve life problems. Science in itself is an inquiry into nature.
Science uses a series of methodical approaches to conduct investigations and researches. The product of the research is taken up by an engineer. The engineer deploys this into the right and applicable technology available. In the clothing company, the product of the investigation are relayed to the engineers who uses technological innovations to design a new tool for use.As a part of a clinical study, a pharmacist is asked to prepare a modification of a standard 22g package of a 2% mupirocin ointment by adding the needed quantity of mupirocin powder to prepare a 3% w/w mupirocin ointment. How many mg of mupirocin powder are required?
Answer:
226.8 mg of mupirocin powder are required
Explanation:
Given that;
weight of standard pack = 22 g
mupirocin by weight = 2%
so weight of mupirocin = 2% × 22 = 2/100 × 22 = 0.44 g
so by adding the needed quantity of mupirocin powder to prepare a 3% w/w mupirocin ointment
mg of mupirocin powder are required = ?, lets rep this with x
Total weight of ointment = 22 + x g
Amount of mupirocin = 0.44 + x g
percentage of mupirocin in ointment is 3?
so
3/100 = 0.44 + x g / 22 + x g
3( 22 + x g ) = 100( 0.44 + x g )
66 + 3x g = 44 + 100x g
66 - 44 = 100x g - 3x g
97 x g = 22
x g = 22 / 97
x g = 0.2268 g
we know that; 1 gram = 1000 Milligram
so 0.2268 g = x mg
x mg = 0.2268 × 1000
x mg = 226.8 mg
Therefore, 226.8 mg of mupirocin powder are required
We have that for the Question "How many mg of mupirocin powder are required? "
It can be said that
[tex]0.2268g[/tex] of mupirocin powder is required
From the question we are told
a pharmacist is asked to prepare a modification of a standard 22g package of a 2% mupirocin ointment by adding the needed quantity of mupirocin powder to prepare a 3% w/w mupirocin ointment
Weight of standard package = 22g
mupirocin = 2%
Therefore,
Weight of mupirocin = [tex]\frac{2}{100}*22[/tex]
[tex]=0.44g[/tex]
Let amount of mupirocin to be added to prepare 3% w/w mupirocin ointment = X
Therefore,
Total weight of ointment = [tex](22 + X)g[/tex]
amount of mupirocin = [tex](0.44+X)g[/tex]
% of mupirocin in ointment = [tex]3\%[/tex]
therefore,
[tex]\frac{3}{100} = \frac{0.44+X}{22+X}\\\\66+3X = 44+100X\\\\X = 0.2268g[/tex]
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Which factors directly affect the magnetic force produced by an electromagnet?
O number of turns in the wire, amount of current
O amount of current, type of force
O length of core, number of turns in the wire
O amount of current, length of core
4. Which employees should be aware of how to turn off power to a shop in an emergency?
Answer:
All employees should know how to work the system
What is believed to be one of the most common mechanisms of concussions? Will give branliest
Answer:
Typical injury mechanism: Direct impact on the head is by far the most common mechanism of concussion. It may be caused by stable objects such as the floor or objects in motion (such as baseball bats or hockey sticks).