Answer:
33.6 mol of the atom strontium contains approximately
3) 2.02 × 10²⁵ atoms of strontium
Explanation:
The number of atoms in one mole of a substance is given by Avogadro's number number, [tex]N_A[/tex], which is presented as follows;
1 mole of a substance contains [tex]N_A[/tex] = 6.022 × 10²³ elementary particles
33.6 mol of a substance will contain 33.6 × 6.02214 × 10²³ elementary particles of the substance
Therefore;
33.6 mol of the atom strontium contains 33.6 × 6.02214 × 10²³ = 2.023439 × 10²⁵ atoms of strontium
33.6 mol of the atom strontium contains ≈ 2.02 × 10²⁵ atoms of Sr.
What is the pH of an aqueous solution of HCl with a hydrogen ion
concentration of [H+] = 6.7 x 10-6 M? Round your answer to the nearest
hundredth.
Answer:
pH = 5.17
Explanation:
pH = -log[H+] = -log(6.7 x 10^-6) = 5.17
Which statement is correct?
A. Physical changes produce new substances; chemical changes do not.
B. Chemical changes produce new substances; physical changes do not.
C. Both physical changes and chemical changes produce new substances.
D. Neither physical changes nor chemical changes produce new substances.
Answer:
B. Chemical changes produce new substances; physical changes do not.
Explanation:
Physical changes only alter appearances, while chemical changes are interactions that create new chemical formulas.
Which region on the map has the highest risk of future landslides? a- Region 1 b-Region 2 c- Region 3 d- there is no way to make comparisons about the risk of future landslides? The subject is science (8th grade)
Answer:
Explanation:
Which region on the map has the lowest risk of future landslides?
WILL MARK BRAINLIEST FOR CORRECT ANSWER
Continue reading from Ruby Bridges’s autobiography.
We drove down North Galvez Street to the point where it crosses Alvar. I remember looking out of the car as we pulled up to the Frantz school. There were barricades and people shouting and policemen everywhere. I thought maybe it was Mardi Gras, the carnival that takes place in New Orleans every year. Mardi Gras was always noisy.
As we walked through the crowd, I didn’t see any faces. I guess that’s because I wasn’t very tall and I was surrounded by the marshals. People yelled and threw things. I could see the school building, and it looked bigger and nicer than my old school. When we climbed the high steps to the front door, there were policemen in uniforms at the top. The policemen at the door and the crowd behind us made me think this was an important place.
It must be college, I thought to myself.
–Through My Eyes,
Ruby Bridges
What evidence in the text supports the idea that Bridges did not realize the significance of her first day? Check all that apply.
“I remember looking out of the car as we pulled up to the Frantz school.”
“I thought maybe it was Mardi Gras.”
“As we walked through the crowd, I didn’t see any faces.”
“[The school] looked bigger and nicer than my old school.”
“The crowd behind us made me think this was an important place.”
“It must be college, I thought to myself.”
Answer: I remember looking out of the car as we pulled up to the Frantz school.”
“I thought maybe it was Mardi Gras.”
“As we walked through the crowd, I didn’t see any faces.”
“[The school] looked bigger and nicer than my old school.”
“The crowd behind us made me think this was an important place.”
“It must be college, I thought to myself.
Explanation:
“I thought maybe it was Mardi Gras.”
“[The school] looked bigger and nicer than my old school.”
“It must be college, I thought to myself.”
How does the environment in which an organism lives determine which traits are adaptations?
can someone plss help me??
Answer:
When an organism lives in a certain environment there is a process called natural selection. Natural selection ensures that the organisms of a species with the best traits suited for an environment will reproduce and pass on those traits to the offspring.
Explanation:
The theory of natural selection was studied by Charles Darwin in The Origin of Species by Means of Natural Selection if you need more information.
Hannah made a diagram to show how plants make their own food. What should Hannah write to fill in the blank in the diagram?
A)
heat from the soil
B)
energy from the Sun
C)
heat from the roots
D)
energy from the wind
PLS SOME HELPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP I NEED HELPPPPPPPPPPP
Answer:
Answer: Energy from the sun.
Explanation:
If you look at the hints it says that it needs something else for a plant to grow and what does a plant need?
Air, Water, and energy from the Sun to make food
Hope this helps :)
Answer:
Energy from the sun
Explanation:
Waste water from nuclear power plants is generally ?
☁️ Answer ☁️
Waste water from nuclear power plants is generally: radioactive.
Hope it helps.
Have a nice day noona/hyung
What type of chemical reaction is demonstrated by this equation? A+BX-AX+B
Answer:
d an acid - base reaction.
Explanation:
Answer:
single replacement
Explanation:Look it up and got it from quizlet it should be right.
What is the type of structure indicated below?
a- ionic structure
b-resonance structure
c- molecular structure
d-electron dot structure
Answer:
Electron dot structure
Explanation:
This is because electron dot structure is the structure that shows or indicate valence electrons of an atom and dots
is use around the element symbols . The number of dots shows the total number of valence electrons that are present in the atom of the molecules.
describe each of the three states of matter (solid, liquid, gas)
Explanation:
In a solid particles are firmly together and are stuck in a regular pattern
in a liquid particles still touch but arent in a fixed pattern
in a gas particles move quickly in all directions
I just need 4-8! Plz hurry!!!!!!!!!!!
Answer:
4: 90N
5: 7.77777m/s
6: 4
7: 12.5609756098
8: 187.5
Explanation:
El etanol combustiona con el oxigeno produciendo dióxido de carbono gaseoso y agua: En un proceso se hacen reaccionar 450.2 g de dioxígeno con 998. 2 g de etanol . a) ¿Cuál de los reactivos es el limitante? b) Calcule la masa de dióxido de carbono que se formará c) ¿ Cuanto del reactivo en exceso quedará sin reaccionar?
Answer:
uh oh stinky uh oh stinky
balanced the equation please Fe + O2 → Fe2O3
Answer: The balanced equation is 4,3,2,
Answer: Balanced equation = 4Fe + 3O2 => 2Fe2O3.
Explanation:
2. How many moles are in 2.8 Liters of CO2 gas?
Answer:
0.125 moles
Explanation:
2.8 litres is equivalent to 2.8dm³
At STP,
1 mole = 22.4 dm³
x mole = 2.8 dm³
Cross multiply
22.4x = 2.8
Divide both sides by 22.4
x = 2.8/22.4
x = 0.125
PLEASE HELP WITH CHEM !! Calculate the [OH-] of each of the following solutions given the [H+]. AND Classify each of the solutions in the question above as either acid, base, or neutral. AND FIND THE PH
pH, pOH, [H+], and [OH-] are all interrelated. For simplicity, we assume that we're working with aqueous solutions at 25 °C.
The following mathematical relations are relevant here:
pH = -log[H⁺]pOH = -log[OH⁻][H⁺] = 10^-pH[OH⁻] = 10^-pOHpH + pOH = 14[H⁺] × [OH⁻] = 10^-14A pH of 7 is neutral; a pH less than 7 is acidic; and a pH greater than 7 is basic.
---
We are given four solutions of varying [H⁺], and we want to find the pH and the [OH⁻]. The pH will tell us whether the solution is neutral, an acid, or a base.
Finding the [OH⁻]Using the relationship [H⁺] × [OH⁻] = 10^-14, we can calculate the [OH⁻] of each solution by dividing 10^-14 by the given [H⁺]:
[OH⁻] = 10^-14/(3.3 × 10^-5) = 3.0 × 10^-10
[OH⁻] = 10^-14/(4.0 × 10^-8) = 2.5 × 10^-7
[OH⁻] = 10^-14/(7.2 × 10^-11) = 1.4 × 10^-4
[OH⁻] = 10^-14/(8.2 × 10^-4) = 1.2 × 10^-11
Note: While not indicated here, the units for [H⁺] and [OH⁻] are moles/liter (M).
Finding the pHTo find the pH of each solution, we take the negative logarithm of the [H⁺] with base 10, i.e., pH = -log₁₀[H⁺]:
pH = -log(3.3 × 10^-5) = 4.48
pH = -log(4.0 × 10^-8) = 7.40
pH = -log(7.2 × 10^-11) = 10.14
pH = -log(8.2 × 10^-4) = 3.09
Note that, for significant figures involving logarithms, the number of decimal places should equal the number of significant figures in the argument of our logarithm (the argument is what we're taking the -log of). Since we're taking the -log of quantities given to two significant figures, our corresponding pH values are given to two decimal places.
Acid, Base, or Neutral?As mentioned above, a pH = 7 is neutral, a pH < 7 is acidic, and a pH > 7 is basic.
4.48 < 7, so the first solution is an acid.
7.40 > 7, so the second solution is a base.
10.14 > 7, so the third solution is a base.
3.09 < 7, so the fourth solution is an acid.
Savvas Realize. Investigation 8 Experiment 1
Answer:
–1065.25 KJ of energy.
Explanation:
From the question given above, the following data were obtained:
4FeO + O₂ —> 2Fe₂O₃ ΔH = –560.66 kJ
From the balanced equation above,
The formation of 2 moles of Fe₂O₃ released –560.66 kJ of energy.
Finally, we shall determine the amount of heat energy released when 3.8 moles of Fe₂O₃ are produced. This can be obtained as follow:
From the balanced equation above,
The formation of 2 moles of Fe₂O₃ released –560.66 kJ of energy.
Therefore, the formation of 3.8 moles of Fe₂O₃ will release
= (3.8 × –560.66)/2 = –1065.25 KJ of energy.
Thus, –1065.25 KJ of energy is released from the reaction.
helllp meee pls . ....... ..... . . . . .
. . . . . . . . . .. . . . . ... .. . . . . ....... . . .. . . .. . . . . . . . . ... .. . . . ....
Your opinion on chocolate
What is your opinion on chocolate, any kind like white chocolate dark, etc. also what do you think is the bad side of chocolate?
Answer:
Milk Chocolate
Explanation:
Some chocolates contain lots of sugar, but for Dark chocolate its healthy
Answer:
Milk chocolate the bad side of chocolate is getting fat
Explanation:
have u ever tried shreks snickers before?
Aliyah found a tarnished silver dollar and recalled that tarnish results when metals react with oxygen or sulfur compounds in the air. She polished the silver dollar to remove the tarnish until it was shiny again. She also polished a copper bracelet and a gold ring. What physical property of these metals makes them shiny?
A. conductivity
B. ductility
C. luster
D. malleability
Answer:
C.
Explanation:
Luster
Which of these do NOT show malleability a) Iron
b) Sulfur
c) Copper
d) Aluminum
Answer:Sulfur
Hope this helps!
Explanation:
Benzoic acid, HC6H5CO2,is a monoprotic acid(only one H+ ionizes)with a Ka=6.5×10^-5. Calculate [H+] and the pH of a .32M solution of benzoic acid. PLEASE ANSWER.
Answer:
[H⁺] = 4.56x10⁻³ M
pH = 2.34
Explanation:
Hello there!
In this case, according to the ionization reaction of benzoic acid:
[tex]HC_6H_5CO_2+H_2O\rightleftharpoons C_6H_5CO_2^++H_3O^+[/tex]
Whereas [tex][H_3O^+]=[H^+][/tex], we can set up the equilibrium expression in terms of [tex]x[/tex] (reaction extent) to obtain:
[tex]Ka=\frac{[C_6H_5CO_2^-][H_3O^+]}{[HC_6H_5CO_2]} \\\\6.5x10^{-5}=\frac{x^2}{0.32-x}[/tex]
However, since Ka<<<1, we can neglect the [tex]x[/tex] on bottom to easily solve for it:
[tex]6.5x10^{-5}=\frac{x^2}{0.32}\\\\x=\sqrt{6.5x10^{-5}*0.32} \\\\x=4.56x10^{-3}[/tex]
Which is actually the same as [H⁺]. Finally, the pH turns out to be:
[tex]pH=-log(4.56x10^{-3})\\\\pH=2.34[/tex]
Best regards!
Because the triple beam balance is zeroed before it is put into use, it measures
A.
volume
B.
weight
C.
the effects of gravity
D.
mass
What element is found in water?
1. Carbohydrate
2. Carbon
3. oxygen
Explanation:
3. the element is oxygen
Which of the following processes occurs with a decreaseentropy of the system
Explanation: Entropy decreases when the number of moles of gas decreases during a reaction. In the case of the correct answer, the number of moles of gas decreases from two to one. When a substance goes from a solid to a gas (sublimation) or from a liquid to a gas (evaporation), entropy increases.
How are a rainforest and a desert different?
Answer:
Difference between Desert Plants and Rainforest Plants. The deserts are very dry land areas that can be hot or cold and experience very less rainfall. On the other hand, rainforests receive an enormous amount of rain. Both are homes to a variety of plants.
Explanation:
Why should we work to protect estuaries? Select all that apply.
PLSSSS
Answer:
1, 3, and 4
Explanation:
I'm guessing, but those make the most sense
Answer:
3 and 4
Explanation:
what is the limiting reactant of 20.0 moles of o2 react with 30.0 moles of h2 according to the following reaction ? 2H2 + O2 = 2H2O
Answer:
The limiting reactant is hydrogen.
Explanation:
According to the balanced equation for synthesis of water, hydrogen is used up twice as fast as oxygen -- we need two moles of H2 for every one mole of O2 when creating water.
Since we have 20 moles of oxygen, this means we would need twice as much hydrogen, or 40 moles, to use it all up. There is only 30 moles of hydrogen, which means that all the hydrogen will be used before the 20 moles of oxygen is used. Hydrogen limits production in this case.
We have that
From the Question we are told that
20.0 moles of o_2
30.0 moles of h_2
Therefore
The ratio
For more information on this visit
Pls help me with this problem
Answer:
2 and 5 would be my answers
Explanation:
True or false?
A limitinh factor is an environmental factor that increases the growth of a population
True or false?
Biomes are characterized by temperature, precipitation, and the plant and animal communities that live there
1. Cancer is a disease in which cells
a. grow and divide uncontrollably. b. die before they can mature.
c. stop producing DNA. d. die during mitosis.
____ 2. Which of these traits is controlled by a gene with multiple alleles?
a. straight hairline b. smile dimples
c. widow’s peak d. blood type
____ 3. Which of these is an example of the benefits of genetic engineering?
a. cross-breeding to create disease-resistant crops
b. creating human insulin to treat people with diabetes
c. analyzing karyotypes and pedigree charts
d. growing a new plant from a cutting
____ 4. A carrier is a person who has
a. one recessive and one dominant allele for a trait.
b. two recessive alleles for a trait.
c. two dominant alleles for a trait.
d. more than two alleles for a trait.
____ 5. Sex-linked genes are genes on
a. the X chromosome only. b. the Y chromosome only.
c. the X and Y chromosomes. d. all 23 pairs of chromosomes.
______ 6. What is the chromosome theory of inheritance?
a. Chromosomes are carried from parents to offspring on hybrids.
b. Genes are carried from parents to offspring on chromosomes.
c. Hybrid pairs of chromosomes combine to form offspring.
d. Codominant genes combine to form new hybrids.
____ 7. How can a mutation affecting skin be harmful to an animal?
a. It can make the animal more visible to its prey or predators.
b. It can cause disease in the animal.
c. It can make the animal resistant to certain diseases.
d. It can make the animal resistant to drugs
______ 8. What happens during meiosis?
a. Two sex cells combine.
b. Chromosome pairs separate and are distributed into new sex cells.
c. Each sex cell copies itself to form four new chromosomes.
d. Chromosome pairs remain together when new sex cells are formed.
Answer:
1. a
2. a.
3. b.
4. a.
5. c.
6. b.
7. a.
8. c.
Explanation: