Answer:
The answer is in the picture.
How many atoms are in 2.17 moles of strontium?
Answer: I think 82.46
Explanation: The atomic number for strontium, or Sr on the periodic table, is 38. With knowing the atomic number, I multiplied that by the number of moles given.
38 × 2.17 = 82.46
I hope this helps!!
The number of atoms present in 2.17 moles of strontium are [tex]1.306774 \times 10^{24}[/tex].
An atom is the smallest indivisible unit of a chemical element that retains the chemical properties of that element. It is the basic building block of matter.
To determine the number of atoms in a given number of moles, we can use Avogadro's number, which is approximately [tex]6.022 \times 10 ^{24}[/tex] atoms per mole.
In this case, we have 2.17 moles of strontium. To find the number of atoms, we multiply the number of moles by Avogadro's number:
Number of atoms = [tex]2.17 moles\times6.022\times 10^{23}[/tex][tex]atoms/mole[/tex]
On calculating this expression:
Number of atoms =[tex]1.306774 \times 10^{24}[/tex]
Therefore, there are approximately [tex]1.306774 \times 10^{24}[/tex] atoms in 2.17 moles of strontium.
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If 381 mL of 9.96 M LiCl is diluted with water to make 750 mL of solution calculate the molarity of the new solution.
Answer:
5.06 M LiCl
Explanation:
To find the new molarity of the solution, you need to (1) find the amount of moles LiCl (via the molarity equation using the original molarity and volume) and then (2) calculate the new molarity (via the molarity equation using the new volume and old moles). The final answer should have 3 sig figs to match the given values.
Molarity (M) = moles / volume (L)
Step (1)
381 mL / 1,000 = 0.381 L
Molarity = moles / volume
9.96 M = moles / 0.381 L
(9.96 M) x (0.381 L) = moles
3.79 = moles
Step (2)
750 mL / 1,000 = 0.750 L
Molarity = moles / volume
Molarity = 3.79 moles / 0.750 L
Molarity = 5.06 M
A camel's hump is a trait that evolved through the process of ____________ to allow the camels to survive for longer periods without water.
A.
natural selection
B.
fossilization
C.
mutualism
D.
genetics
Answer:
Natural Selection
The answer is:
A. Natural Selection
Which option below has the correct order of steps to complete a stoichiometric calculation to determine percent yield?
A. Write a balanced equation, determine the limiting reactant, calculate the theoretical yield, calculate the percent yield
B. Write a balanced equation, determine the excess reactant, calculate the theoretical yield, calculate the percent yield
C. Determine the excess reactant, write a balanced equation, calculate the theoretical yield, calculate the percent yield
D. Calculate the percent yield, determine the limiting reactant, write a balanced equation, calculate the theoretical yield
To determine the percentage yield, do the following:
Write the balance equationDetermine the limiting reactant Calculate the theoretical yieldCalculate the percentage yield (Option A)What is stoichiometry?Stoichiometry simply defined the relationships of the various quantities as they react in a chemical reaction
Scientist are mostly inquisitive and as such may want to determine the percentage yield of a reaction even before carrying it out.
How to determine the percentage yieldTo determine the percentage for a given reaction, we must set up the following:
Write the balance equationDetermine the limiting reactant Calculate the theoretical yieldCalculate the percentage yieldFrom the above, we can conclude that option A gives the right steps if we must successfully determine the percentage yield of a reaction.
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Answer:
A
Explanation:
Edge 2022
At ground level, how are rain and hail similar?
They are forms of water in its liquid state.
They occur when the temperature is below freezing.
They can occur when the air is hot and moist.
They are most common in the winter.
They are forms of water in its liquid state at ground level. Thus, the correct option is A.
What is hailstrom?Precipitation, or water in the atmosphere, forms hail. When water drops freeze together in the chilly higher parts of thunderstorm clouds, hail is the result.
When a water droplet is lifted by an updraft from a thunderstorm over the freezing point of the atmosphere, hail is created. The super-cooled water or water vapor that the frozen water droplet accretes later freezes when it comes into touch with it. A hailstone grows as a result of this process.
When water vapor from the atmosphere condenses into liquid water droplets, they become heavy enough to fall as a result of gravity.
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Answer:A
Explanation:
.
What is the rule when "ao" or "oo" are together when naming covalent bonds
They are converted into a single “o” when "ao" or "oo" are together when naming covalent bonds.
What is a covalent bond?A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms.
Sometimes, while naming the chemical compounds, a problem arises when compounds with “ao” and “oo” are written with -ide name. Conventionally, they are converted into a single “o”.
For example, the “ao” in the dichlorine hept-ao-xide ([tex]Cl_2O_7[/tex]). This “ao” in the [tex]Cl_2O_7[/tex] can be converted into “o”. As the result, the correct name of this compound would be dichlorine hept-o-xide.
Hence, they are converted into a single “o” when "ao" or "oo" are together when naming covalent bonds.
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▸ Exam Instructions
Question 15 of 20:
Select the best answer for the question.
15. Why can over-the-counter medications be sold to consumers without the need for a prescription?
A. They're found to give benefits to all people, regardless of whether a patient is ill or not.
B. They're all covered by insurance companies and therefore a prescription isn't necessary.
C. They're safe to use without the regulation of a physician, according to a regulatory agency.
D. They're considered the most important and consumers are encouraged to keep stock of certain types at home.
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Which of these is a reason an engineer may choose to use a prefabricated
building component?
A. She wants to make the building more original and unique.
B. She wants to use standard materials to minimize negative
environmental impacts.
C. She wants to make the building safer.
OD. She is not on a strict timeline.
Answer:
B.
Explanation:
customization requires more material, more machine time which can creates a greater impact on the environment in the sense of pollution (travel by the extra employees, creation of custom materials, increased machine running time). Good luck in your studies. Hope this answers your question in full.
Although these days many people have “self-cleaning” ovens, if your oven gets really dirty you may have to resort to one of the spray-on oven cleaner preparations sold in supermarkets. What evidence is there that such oven cleaners work by a chemical reaction?
Oven cleaners typically contain a layer of sodium hydroxide, which converts the greases and oils on the oven walls into soap, which can then be cleaned away more easily.
What is an oven?A chamber used for baking, heating, or drying.
Self-cleaning ovens emit dangerous fumes into the air with an unpleasant burning smell. Self-cleaning ovens reach high temperatures and produce fumes from the cooking of food particles. These fumes circulate with the air and can affect the home substances.
Spray-on oven cleaner ovens contain a layer (sodium hydroxide), which converts the greases of the oven walls into soap, which can then be cleaned away more easily.
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Select only one most suitable description
A substance decomposes with a rate
constant of 9.05 x 10-4 s¹. How long does
it take for 15.0% of the substance to
decompose?
Answer:
The time required to decompose the substance is 360 seconds.
Which of the following tool components is unlikely to present a hazard
Gloves is the tool component which will unlikely present a hazard in this scenario.
What is Hazard?
This is referred to as potential source of harm when performing various types of activities.
Gloves will unlikely cause harm as it is used to prevent the risk of electric shock when handling electrical devices which is why it is the most appropriate choice.
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4HCl(g)+O2(g)⟶2Cl2(g)+2H2O(g) Calculate the number of grams of Cl2 formed when 0.385 mol HCl reacts with an excess of O2. mass: g
The number of grams of Cl2 formed when 0.385 mol HCl reacts with an excess of O2 is 13.6675 g.
What are moles?A mole is defined as 6.02214076 × [tex]10^{23}[/tex] of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
Given data:
Moles of hydrochloric acid = 0.385 mol
Mass of chlorine gas =?
Chemical equation:
4HCl + O₂ → 2Cl₂ + 2H₂O
Now we will compare the moles of Cl₂ with HCl.
HCl : Cl₂
4 : 2
0.385 : 2÷4× 0.385 = 0.1925 mol
Oxygen is present in excess that's why the mass of chlorine produced depends upon the available amount of HCl.
Mass of Cl₂ :
Mass of Cl₂ = moles × molar mass
Mass of Cl₂ =0.1925 mol × 71 g/mol
Mass of Cl₂ = 13.6675 g
Hence, the number of grams of Cl2 formed when 0.385 mol HCl reacts with an excess of O2 is 13.6675 g.
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Which of the following sets of descriptors matches the molecule below?
Image of two hydrogen atoms bonded to one oxygen atom to form H2O, or water.
A. Simple structure, molecule, single bonds, two elements
B. One element, triple bond, molecule, diatomic
C. Giant structure, single bond, compound, one element
D. Compound, allotrope, double bond, giant structure
Answer: A. Simple structure, molecule, single bonds, two elements
Air pressure is measured in pascals. For a professional American football game, the ball should be inflated to about 90,000 pascals. Scientists studied the effects of air temperature on the pressure inside American footballs by taking these steps:
1. Prepare 100 footballs.
2. Measure each football's air pressure.
3. Divide footballs into 10 groups.
4. Place the groups in different lockers cooled to different air temperatures.
5. After 12 hours, remove the footballs from lockers.
6. Measure each football’s pressure again.
7. Compare the new pressures to the starting pressures.
What two terms best describe the variable "air pressure inside the football" in this experiment?
independent, qualitative
independent, quantitative
dependent, qualitative
dependent, quantitative
The variable "air pressure inside the football" in this experiment is quantitative and dependent variable. Hence, option D is correct.
What is the dependent variable?The dependent variable is the variable that is being measured or tested in an experiment.
In the experiment, the scientist filled the footballs with fix quantity of pressure which was then kept for 12 hours. After 12 hours the pressure inside the footballs was again measured. Pressure here is a quantitative variable.
Since the air temperature is an independent variable. The pressure being the dependent variable depends upon the temperature of the air.
Independent variable; The variable which does not depends upon any other variable.
Dependent variable; The variable which depends upon the independent variable or varies with the change independent variable.
Qualitative variables are variables which cannot be expressed in form of numbers. They generally convey the characteristic, category, quality or type.
Whereas Quantitative variables are the variables which can be expressed in the form of numbers. These are the variables which exist along the continuous sequence.
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Please help !!!
Suppose there are 29.9 g of butane gas in a barbecue lighter. How many moles of butane gas is that ?
Question 4 of 15
A compound with the empirical formula CH₂ has a molar mass of 42 g/mol. What is the molecular formula for this compound?
molecular formula:
3CH₂
Attempt 1
Incorrect
(CH₂)n=42
(14)n=42
n=3
C₃H₆
Balance the equation using the
correct coefficient
2Li + 2H2O____ 2LiaOH + 2H2
Answer:
2 Li + 2 H2O --> 2 LiaOH + 1 H2
Determine the mass of SO₂ that contains 6.075 × 10^26 S atoms.
Avogadro's law states that in a mole of any substance, there are [tex]6.022 \times 10^{23}[/tex] atoms. This means that in the given sample, there are
[tex]\frac{6.075 \times 10^{26}}{6.022 \times 10^{23}}=1008.8010627 \text{ mol}[/tex]
The atomic mass of sulfur is 32.06 amu.The atomic mass of oxygen is 15.9994 amu.So, the atomic mass of sulfur dioxide is
[tex]32.06+2(15.9994=64.0588 \text{ g/mol}[/tex]
Therefore, the mass is:
[tex](64.0588)(1008.8010627)=\boxed{64620 \text{ g (to 4 sf)}}[/tex]
Which statement describes an electron?
O It has a positive charge and is located in the nucleus.
OIt has a positive charge and is located in orbitals around the nucleus.
O It has a negative charge and is located in the nucleus.
O
It has a negative charge and is located in orbitals around the nucleus.
Answer:
D.) It has a negative charge and is located in orbitals around the nucleus.
Explanation:
Electrons always have a negative charge. Since electrons can be shared or donated/received, they must be located in the orbitals around the nucleus. Protons, which have a positive charge, and neutrons, which are neutral, are located in the nucleus.
A vessel with a volume of 25.1 L contains 2.80 g of nitrogen gas, 0.605 g of hydrogen gas, and 79.9 g of argon gas. At
25°C, what is the pressure in the vessel?
Select one:
a. 58.7 atm
b. 2.73 atm
c. 0.196 atm
d. 81.0 atm
e. 2.34 atm
2.73 atm is the pressure in the vessel. Hence, option B is correct.
What is an ideal gas equation?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
PV=nRT, where n is the moles and R is the gas constant. Then divide the given mass by the number of moles to get molar mass.
Given data:
P= ?
V= 25.1 L
[tex]n= \frac{m}{molar \;mass \;of \;nitrogen} + \frac{m}{molar \;mass \;of \;hydrogen } +\frac{m}{molar \;mass \;of \;argon}[/tex]
[tex]n= \frac{2.80 g}{14} + \frac{0.605 g}{1} +\frac{79.9 g}{40}[/tex]
n= 2.8025
R= [tex]0.082057338 \;L \;atm \;K^{-1}mol^{-1}[/tex]
T=25°C + 273= 298 K
Putting value in the given equation:
[tex]\frac{PV}{RT}=n[/tex]
[tex]2.8025 = \frac{P\; X \;25.1 \;L}{0.082057338 \;L \;atm \;K^{-1}mol^{-1} X 298}[/tex]
P = 2.73 atm
2.73 atm is the pressure in the vessel. Hence, option B is correct.
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Question 21
A sample of rainwater has a pH of 3.5. What ion is sure to be present in relatively
large concentration in this rain sample?
H3O+
SO4²-
OH
HSO4
A sample of rainwater with a pH of 3.5 is sure to contain a large concentration of [tex]H_3O^+[/tex]
pH scaleA pH value of 7 downward is said to be acidic. Upward of 7 is said to be basic. A pH of 7 on the dot is said to be neutral.
An acid is defined as a substance that produces [tex]H_3O^+[/tex] as its only positively charged ion in solution.
Thus, rainwater with a pH of 3.5 is acidic and will contain a high concentration of [tex]H_3O^+[/tex].
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uses of radio isotopes
Answer:
1. Used in many smoke detectors for homes and businesses to measure levels of toxic lead in dried paint sample to ensure uniform thickness in rolling processes like steel and paper production and to help determine where oil wells should be drilled.
2.Used to treat cancerous tumors to measure correct patient dosages of radioactive pharmaceutical to measure and control the liquid flow in oil pipelines to tell researchers whether oil wells are plugged by sand and to ensure the right fill level for packages of food, drugs, and other
products.
3.Used in medical diagnosis
4.Used to treat thyroid disorders. (Graves’s disease).
5.Used in molecular biology and genetics research.
6.Used in nuclear medicine for lung ventilation and blood flow studies.
7.Used in dental fixtures like crowns and dentures to provide a Uranium-234 natural color and brightness.
8.Used in electric blanket thermostats and to gauge the thickness of thin plastics, thin sheet metal, rubber, textile and paper.
A cubic meter of air was sampled at 1.0 ATM and 40 C.
An ion chromatographic analysis of that sample found it to contain 12 micrograms of NO2.
How many ppb of NO2 is in the air?
The amount of nitrogen oxide in the air sample is determined as 7.01 ppb.
Amount of Nitrogen oxide in the air
The amount of Nitrogen oxide (NO2) in the air in parts per billion (ppb) is calculated as follows;
12 micrograms of NO2 = 12 μg = 12 x 10⁻⁶ g
PV = nRT
V = nRT/P
Where;
V is volume of NO2 gasn is number of moles of NO2 gasT is temperature = 40 C = 313 Kn = m/M
M = molar mass of NO2 = 46
n = 12 x 10⁻⁶/46
n = 2.73 x 10⁻⁷ mole
V = (2.73 x 10⁻⁷ x 0.082057 x 313)/(1)
V = 7.01 x 10⁻⁶ L
V = 7.01 x 10⁻⁹ m³
Amount of NO2 In parts per billion= (Volume of NO2)/(volume of air) x 10⁹
= (7.01 x 10⁻⁹)/(1) x 10⁹
= 7.01 ppb
Thus, the amount of nitrogen oxide in the air sample is determined as 7.01 ppb.
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3-chloropropylamine what is?
Answer:
a chemical compound
What net force is required to cause a 12,000 kg airplane to accelerate at a rate of 5.2 m/s
Explain why the compound Cl2O has a low melting and boiling point.
5. In an oxyacetylene welding torch, acetylene (C2H2) burns in pure oxygen with a very hot flame. The reaction is: 2 C2H2 + 5 O2 → 4 CO2 + 2 H2O.
a. What is the mass of C2H2 that is consumed if 35.0 grams of oxygen is allowed to react?
b. How many milliliters of water will be produced when the 35.0 grams of oxygen from part a. above is allowed to react. The density of water is 1.0 gram
Answer:
[tex]a. \ \ \ \text{The mass of ethylene is 11.375 g}. \\ \\ b. \ \ \ \text{The volume of water produced is 7.875 ml}.[/tex]
Explanation:
a. According to the chemical equation for the combustion of ethylene, 5
moles of oxygen are required to react with 2 moles of ethylene, hence
[tex]m_{C_{2}H_{2}} \ = \ 35 \ \text{g} \ \times \ \displaystyle\frac{1 \ \text{mol}}{\left(2 \times 16 \right) \text{g}} \ \times \ \displaystyle\frac{2 \ \text{mol}}{5 \ \text{mol}} \ \times \ \displaystyle\frac{\left(12 \ \times \ 2 \ + \ 1 \ \times \ 2 \right) \ \text{g}}{1 \ \text{mol}} \\ \\ m_{C_{2}H_{2}} \ = \ 11.375 \ \text{g}[/tex]
b. Similarly, 5 moles of oxygen are required as a reactant to produce 2
moles of water, thus
[tex]m_{H_{2}O} \ = \ 35 \ \text{g} \ \times \ \displaystyle\frac{1 \ \text{mol}}{\left(2 \times 16 \right) \text{g}} \ \times \ \displaystyle\frac{2 \ \text{mol}}{5 \ \text{mol}} \ \times \ \displaystyle\frac{\left(1 \ \times \ 2 \ + \ 16 \right) \ \text{g}}{1 \ \text{mol}} \\ \\ m_{H_{2}O} \ = \ 7.875 \ \text{g}[/tex]
Given that the density of water is [tex]1.0 \ \text{g ml}^{-1}[/tex], therefore
[tex]\rho_{H_{2}O} \ = \ \displaystyle\frac{m_{H_{2}O}}{V_{H_{2}O}} \\ \\ V_{H_{2}O} \ = \ \displaystyle\frac{m_{H_{2}O}}{\rho_{H_{2}O}} \\ \\ V_{H_{2}O} \ = \ \displaystyle\frac{7.875 \ \text{g}}{1.0 \ \text{g ml}^{-1}} \\ \\ V_{H_{2}O} \ = \ 7.875 \ \text{ml}[/tex]
11.375 g ethylene is consumed if 35.0 grams of oxygen is allowed to react and 7.875 ml of water will be produced when the 35.0 grams of oxygen is allowed to react.
What are moles?A mole is defined as 6.02214076 ×[tex]10^{23}[/tex] of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
According to the chemical equation for the combustion of ethylene, 5
moles of oxygen are required to react with 2 moles of ethylene, hence
[tex]m_{_C_2_H_2}[/tex] [tex]= 35gX \frac{1 mol}{(2 \;X\; 16)g } X \frac{2 mol}{(5\;mol )} X \frac{26g}{1 mol }[/tex]
[tex]m_{_C_2_H_2} = 11.375 g[/tex]
Similarly, 5 moles of oxygen are required as a reactant to produce 2 moles of water, thus
[tex]m_{_H_2_O} = 35gX \frac{1 mol}{(2 \;X\; 16)g } X \frac{2 mol}{(5\;mol )} X \frac{18g}{1 mol }[/tex]
[tex]m_{_H_2_O} = 7.875 g[/tex]
Given that the density of water is [tex]1.0g ml^{-1}[/tex], therefore
[tex]Density = \frac{Mass \;of \;water}{Volume \;of \;water}[/tex]
[tex]Volume \;of \;water = \frac{7.875}{1.0 g ml^{-1}}[/tex]
The volume of water = 7.875 ml
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Explain how they would make solutions of the sulfuric acid at five different concentrations
The sulfuric acid can be constituted into different concentrations using distilled water as a diluent.
What is dilution of acid?Dilution of acid is defined as the decrease in the concentration of an acid using water.
For sulfuric acid to be diluted, it is slowly added to distilled water using the following guidelines:
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Please help. I’m confused on where to even start
Answer:
b
Explanation:
because it freezer in temperature