Answer:
The chemical elements are arranged in order of increasing atomic number. The horizontal rows are called periods and the vertical columns are called groups. Elements in the same group have similar chemical properties. This is because they have the same number of outer electrons and the same valency.
which of the following elements have the same number of valence electrons?
l. nitrogen (N)
ll. oxygen (O)
lll. fluorine (F)
lv. sulfur (S)
v. selenium (Se)
A. IV, and V
B. I, II, and III
C. I, II, and IV
D. II, IV, and V
The answer is II. Oxygen, IV. Sulfur, and V. Selenium.
Explanation:
Going down the list that was provided, we can use the periodic table of elements to determine the valence electrons.
- Nitrogen has 5 valence electrons
- Oxygen has 6 valence electrons
- Fluorine has 7 valence electrons
- Sulfur has 6 valence electrons
- Selenium has 6 valence electrons
Since oxygen, sulfur, and selenium all have 6 valence electrons, then that is the correct answer.
I hope this helps you!
What are stationary fronts?
what is the mass of a sample of glass (specific heat = 0.50 J/g°C), if it requires 490 J of heat to raise the temperature from -18.0°C to 0.0°C?
Answer:
54.4g
Explanation:
Let's first take account of what we have and what we're looking for.
Q = heat energy (Joules, J)= 490 J
m = mass of a substance= ??
c = specific heat (units J/kg∙K)= 0.50 J/g°C
∆T = change in temperature (Kelvins, K)= Final temperature - initial temperature -> (0C - (-18C))
We can use Q = mc∆T to determine the mass, we'll rearrange the formula to solve for mass, so it'll be: m=Q/c∆T. Let's plug it all in.
m= 490J / (0.50 J/g°C x ((0C - (-18C)))
m= 490J / (0.50 J/g°C x (0 + 18))
m= 490J / (0.50 J/g°C x 18)
m= 490J / 9 J/g
m= 54.4g of glass
Create 3 multiple choice questions on
photosynthesis and the tropisms.
Number your questions using 1,2,3
and
your answer choices using a,b,c.
Example:
1)What three things are required in order for
photosynthesis to take place
A)Sugar, glucose plants
B)Radiant energy, water, oxygen
C)Radiant energy, water, carbon dioxide
Help ASAP!
47.9 ml hrdrogen is collected at 26° Celsius and 718 torr. Find the volume occupied at STP
Answer:
41.45 mL
Explanation:
Applying the general gas equation,
PV/T = P'V'/T'............... Equation 1
Where P = Initial pressure of hydrogen, V = Initial volume of hydrogen, T= Initial Temperature of hydrogen, P' = Final pressure of hydrogen, V' = Final Volume of Hydrogen, T' = Final Temperature.
make V' the subject of the equation
V' = PVT'/TP'................ Equation 2
Given: P = 718 torr = (718×133.322) N/m² = 95725.196 N/m², V = 47.9 mL = 0.0479 dm³, T = 26 °C = (26+273) = 299 K, T' = 273 K, P' = 101000 N/m²
Substitute these values into equation 2
V' = ( 95725.196×0.0479×273)/(299×101000)
V' = 0.04145 dm³
V' = 41.45 mL
Please help! Using table of average bond energies below the (trianglesymbol)H for the reaction is ___kJ
Answer:
-217 kJ
Explanation:
ΔH = reactant energy - product energy
ΔH = [(C-H) × 2 + (C≡C)] + [2 × H-I] - [(I-C) × 2 + (C-H) × 4 + (C-C)]
ΔH = [ (413 × 2 ) + 839 + 2(299)] - [(240 × 2) + (413 × 4) + 348]
ΔH = [826 +839 + 598] - [ 480 +1652 + 348]
∴ ΔH = -217
1. What is the function of the circulatory system? * 10 points A. Provide blood with oxygen from the air, & to get rid of carbon dioxide B. Carry oxygen, nutrients, waste, & to fight pathogens C. Secrete hormones to regulate the body and maintain homeostasis D. Produce red blood cells, white blood cells, & platelets
Answer:
B. Carry oxygen, nutrients, waste, & to fight pathogens
Explanation:
The circulatory system refers to all organs and tissues involved in carrying blood and lymph around the body.
The circulatory system carries oxygenated blood from the heart to cells and deoxygenated blood back to the heart.
Nutrients are carried in the blood to cells in different parts of the body and waste products are also carried from cells in the blood.
White blood cells is a component of blood in the circulatory system that fights off diseases.
What problem would a person have if the nucleic acid in one of his or her
cells was damaged?
A. That cell could not perform photosynthesis.
B. That cell could not join monosaccharides,
O C. That cell could not contain carbohydrates.
D. That cell could not produce certain proteins.
SUBMIT
If a person will have damaged nucleic acid, they can not form certain proteins. The correct option is D.
What is relation between protein and nucleic acids?Protein is a polypeptide-based molecule. Polypeptides are a sort of biological particle made up of amino acids that form chains.
Nucleic acid is a kind of macromolecule composed of a lengthy polynucleotide chain that encompasses deoxyribonucleic acid and ribonucleic acid.
Proteins are built under an elaborate process orchestrated by the nucleic acids deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) (RNA).
Protein biosynthesis is the process of constructing protein chains from individual amino acids in a specific sequence.
Deoxyribonucleic acid stores the information that cells necessitate to produce proteins.
A related type of nucleic acid widely recognized as ribonucleic acid (RNA) exists in various molecular forms and serves a variety of cellular functions, including protein synthesis.
Thus, the correct option is D.
For more details regarding nucleic acids, visit:
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Which of these properties contribute to homeostasis? Click on the correct
responses.
Select 3 correct answer(s)
Blood pH
Reflex reactions
Flight or flight
Body temperature
Blood glucose
Answer:
Its Body Temperature, Blood glucose, and Blood pH
Explanation:
I checked in Body systems and Homeostasis in Florida.org :>
If the volume of a gas at 0.5 atm changes from 150 mL to 75 mL, what is the new pressure?
Answer:
1 atmExplanation:
The new pressure can be found by using the formula for Boyle's law which is
[tex]P_1V_1 = P_2V_2[/tex]
Since we're finding the new pressure
[tex]P_2 = \frac{P_1V_1}{V_2} \\[/tex]
We have
[tex]P_2 = \frac{0.5 \times 150}{75} = \frac{75}{75} = 1 \\ [/tex]
We have the final answer as
1 atmHope this helps you
Calculate the pH of a 0.00100 molar solution of HBr?
PLEASE DO NOT GIVE ME A LINK
Answer:
pH of a 0.00100 molar solution of HBr = 3
Explanation:
You get the -log of the molarity to get the pH or the pOH, depending on whether the substance is an acid or a base.
If the substance is an acid, getting the -log of its molarity would get you the pH.
If the substance is a base, getting the -log of its molarity would get you the pOH.
Since HBr is an acid, you will get the pH of it by getting the -log of its molarity, which in this case is 0.001
-log(0.001) = 3
(btw, when the pH and the pOH are added together, you get 14, so the pOH of this solution of HBr is 14 - 3, which is 11)
The pH value of the molar solution is mathematically given as
pH= 3
What is the pH of 0.00100 molar solution of HBr?Question Parameters:
the pH of a 0.00100
Generally, the equation for the pH value is mathematically given as
pH = - log([H+])
Where
[H+] = [HBr]
[H+] = 0.001 M
Hence
pH = - log([H+])
pH = - log(0.001)
pH= 3
Read more about pH value
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Explain A student wants to increase the maximum amount of sugar that can dissolve in water. She crushes the sugar and then stirs it into the water. Does this work?
Explanation:
When the student crushes sugar there there occurs an increase in the number of molecules or particles of sugar. This means that now more number of sugar particles (solute) are able to interact with water (solvent).
Therefore, there will be more number of collisions taking place between the solute and solvent molecules.
As a result, sugar will dissolve readily into water as there is an increase in interaction between solute and solvent particles.
Thus, we can conclude that when he crushes the sugar and then stirs it into the water then it will work as this leads to more interaction or collisions between the solute and solvent particles.
Describe how crude oil is formed.
Explanation:
crude oil takes thousands of years before forming.
it takes place when animals and plants die...later they decompose especially the ones in water ..the ones on land burn as fossil fuels and go back to the atmosphere through combustion..the decomposed materials turn into crude oil in the ocean where it's extracted and separated through fractional distillation into several oils such diesel, petroleum, coalter e.t.c
If 1.00 L of gas at 1.00 atm of pressure is compressed to a volume of 0.473 L, what is the new pressure of the gas?
Which gas law formula should you use to solve this problem?
-Avogadro’s Law
-Boyle’s Law
-Charles’ Law
Answer:
2.114 atm
Explanation:
Since it is just pressure and volume, use Boyle's Law
P1V1 = P2V2
Then plug in numbers
(1 atm)(1 L) = P2(.473 L)
P2 = 2.114 atm
Explain the laboratory preparation of hydrogen
Answer:
laboratory preparation off Hydrogen: Hydrogen is prepared in the laboratory by the action of the dilute hydrochloric acid or dilute sulphuric acid on granulated zinc. Use of Granulated Zinc Granulated zinc contains an impurity like copper which acts as a positive catalyyst.
Explanation:
Hope this helps!
4. Nowadays, clinical thermometer is replaced by digital thermometer,why?
Answer:
Digital thermometer are used these days instead of clinical thermometers because: Digital thermometers are designed to be more accurate. Most digital thermometers have digital screening which extract temperature of wherever you are measuring.Need help on this question asap pleasee
No links
Answer:
Endothermic
Explanation:
An endothermic reaction is one in which energy is absorbed while an exothermic reaction is one in which energy is given out(evolved).
If we look at the reaction as written; 3C(graphite) + 3H2(g) + 88kcal -------> C3H8(g), we will notice that;
i) 88kcal of energy had to be absorbed for the reaction to occur
ii) The enthalpy change for the reaction is positive.
Since energy must be taken in to drive the forward reaction, then the reaction is endothermic as written.
Dinitrogen oxide (N2O) gas was generated from the thermal decomposition of ammonium nitrate and collected over water. The wet gas occupied 123 mL at 21◦C when the atmospheric pressure was 760 Torr. What volume would the same amount of dry dinitrogen oxide have occupied if collected at 760 Torr and 21 ◦C? The vapor pressure of water is 18.65 Torr at 21◦C. Answer in units of mL.
Answer:
119.98 mL
Explanation:
Initial volume V1 = 123 ml
Initial temperature = T1 = 21◦C + 273 = 294 K
Initial pressure P1 = 760 Torr - 18.65 Torr = 741.35 Torr
Final volume V2= ???
Final temperature = T2= 21◦C + 273 = 294 K
Final pressure P2 = 760 Torr
From;
P1V1/T1= P2V2/T2
P1V1T2 = P2V2T1
V2 = P1V1T2/P2T1
V2= 741.35 * 123 * 294/760 * 294
V2 = 119.98 mL
How many grams of HCL are needed to make 500.0 mL of a 0.100 M solution?
Answer:
1.44 g
Explanation:
The problem gives you the molarity and volume of the target solution, so right from the start you know that you can use that information to determine the number of moles of hydrochloric acid that it must contain.
So, molarity measures a solution's concentration in terms of how many moles of solute, which in your case is hydrochloric acid, you get per liter of solution.
A
0.158 M
hydrochloric acid solution contains
0.158
moles of hydrochloric acid for very liter of solution. Since you're dealing with
250 mL
, the equivalent of
1
4
th
of a liter, your solution will contain
250
mL
⋅
1
L
10
3
mL
⋅
0.158 moles HCl
1
L
=
0.0395 moles HCl
Now that you know how many moles of hydrochloric acid are needed to prepare your solution, use the compound's molar mass to convert this to grams
0.0395
moles HCl
⋅
36.46 g
1
mole HCl
=
∣
∣
∣
∣
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
a
a
1.44 g
a
a
∣
∣
−−−−−−−−−−
Explanation:
Please brainliest.
someone please help meeeee, i’ll help u if u help meeeeeeeeee :)
John (travel) to Russia next week correct the tense
Answer:
hi
Explanation:
John will travel to Russia next week
hope it helps
have a nice day
Answer:
Your answer will be..
John will travel to Russia next week.
Explanation:
He will travel NEXT week so we need to say that he will travel next week.
This may help:
Past tense: We use -ed because that shows the we already did or finished it. EX: We traveled to Russia over the Spring break
Current Tense: You will use -ing to show that you are traveling in the current time. EX:We are traveling to Russia.
Future tense: You might use -ing or keep it the root word. EX: We will be traveling to Russia next week.
We will travel next week.
Hope it helped! Please mark me brainliest! I love helping and I spend a lot of time explaing the answers. Thanks!
~King Sulay~
What is the concentration, in M, if 227 grams of Na2SO4 are dissolved in 1.10
liters?
A 206 M
B 5.11 M
C 2.83 M
D 1.45 M
Answer:
D 1.45 M
Explanation:
If I contain 2.5 moles of gas in a container with a volume of 45 liters and at a temperature of 261 K, what is the pressure inside the container in atmospheres?
Answer:
The correct answer is "[tex]1.21\times 10^5 \ Pa[/tex]".
Explanation:
The given values are:
Number of moles,
n = 2.5 moles
Volume,
V = 45 liters
Temperature,
T = 261 K
As we know,
⇒ [tex]PV=nRT[/tex]
or,
⇒ [tex]P=\frac{nRT}{V}[/tex]
On substituting the values, we get
⇒ [tex]=\frac{2.5\times 0.0821\times 261}{45}[/tex]
⇒ [tex]=\frac{53.57}{45}[/tex]
⇒ [tex]=1.19 \ atm[/tex]
On converting it in Pa, we get
⇒ [tex]=1.19\times 1.01325\times 10^5[/tex]
⇒ [tex]=1.21\times 10^5 \ Pa[/tex]
22. Most plates have a convergent boundary on one side and a
divergent boundary on the other. *
O a true
O b. false
Answer:
the answer for this question is true
what ingredients are needed to turn the cake mix into cake batter
Answer:
Ingredients
2 ⅓ cups all-purpose flour.
1 tablespoon baking powder.
¾ teaspoon salt.
1 ½ cups white sugar.
½ cup shortening.
2 eggs.
1 cup milk.
1 teaspoon vanilla extract.
Explanation:
When reacting Na with Cl2 , we calculated that the theoretical yield should be 12.5 grams. Our actual yield was 13.0 grams. What is the percent yield?
Answer:
[tex]\boxed {\boxed {\sf 104 \%}}[/tex]
Explanation:
Percent ratio is the ratio of the actual yield to the theoretical yield. The formula is below.
[tex]Percent \ Yield} = \frac{{Actual \ Yield}}{{Theoretical \ Yield}} \times 100 \%[/tex]
The reaction of sodium and chlorine should theoretically yield 12.5 grams, but the actual yield was 13.0 grams.
actual yield= 13.0 gtheoretical yield = 12.5 gSubstitute these values into the formula.
[tex]Percent \ Yield} = \frac{{13.0 \ g }}{{12.5 \ g}} \times 100 \%[/tex]
Divide.
[tex]Percent \ Yield} = 1.04 \times 100 \%[/tex]
Multiply.
[tex]Percent \ Yield= 104 \%[/tex]
For this reaction, the percent yield is 104%
25 g of 116oC steam are bubbled into 0.2384 kg of water at 8oC. Find the final temperature of the system.
Answer: The final temperature of the system will be [tex]13.14^0C[/tex]
Explanation:
[tex]heat_{absorbed}=heat_{released}[/tex]
As we know that,
[tex]Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})[/tex]
[tex]m_1\times c_1\times (T_{final}-T_1)=-[m_2\times c_2\times (T_{final}-T_2)][/tex] .................(1)
where,
q = heat absorbed or released
[tex]m_1[/tex] = mass of steam = 25 g
[tex]m_2[/tex] = mass of water = 0.2384 kg = 238.4 g (1kg=1000g)
[tex]T_{final}[/tex] = final temperature = ?
[tex]T_1[/tex] = temperature of steam = [tex]116^oC[/tex]
[tex]T_2[/tex] = temperature of water = [tex]8^oC[/tex]
[tex]c_1[/tex] = specific heat of steam = [tex]1.996J/g^0C[/tex]
[tex]c_2[/tex] = specific heat of water= [tex]4.184J/g^0C[/tex]
Now put all the given values in equation (1), we get
[tex]25g\times 1.996J/g^0C\times (T_{final}-116)=-[238.4g\times 4.184J/g^0C\times (T_{final}-8)][/tex]
[tex]T_{final}=13.14^0C[/tex]
Therefore, the final temperature of the system will be [tex]13.14^0C[/tex]
i need answers for each one of these questions, or an explanation on how to find them on a calculator
Answer:
(9.03x10^-14)x(8.455x10^20)=7.634865x10^7
(5.2x10^11)/(2.10x10^-4)=2.476190x10^15
(7.67x10^12)x(3.8x10^15)=29146000000000000000000000000
(9.237x10^20)/(4.5x10^-6)=2.0526x10^26
Explanation:
How many grams are in 4.00 moles of Cr2O3?
Answer:
607.9616 grams
Explanation:
Hope this helped!!
Outline the steps for a mass-mass stoichiometry problem.