Which best describes why animals need the energy in food?
A for growth and body repair
B for transpiration and growth
C for body repair and photosynthesis
D for cell reproduction and transpiration
Answer:
A for growth and body repair
Explanation:
B, C, and D don't have anything to do with animals.
A compound contains 53% Al and 47% O by mass. What
is the empirical formula of this compound?
Answer:
Al2O3
Explanation:
Empirical formula is found by converting percent composition into a mole ratio.
First, assume you have a 100g sample of the substance. This allows you to make your percent composition into grams.
100% = 100g
53% = 53g Al
47% = 47g O
Next, divide each substance's mass by their molar mass. This converts your number to moles.
[tex]53g Al / 27g Al = 1.96 mol\\\\47g O/16g O = 2.93mol[/tex]
Next, divide both mol answers by the smallest number of moles.
[tex]1.96mol/1.96mol = 1\\2.93mol/1.96mol = 1.5[/tex]
Usually, these answers would be your subscripts for your empirical formula. However, we cannot have a decimal subscript, so we will multiply our answers by a factor of 2 to get to a whole number. This gives us 2 moles of Al and 3 moles of oxygen, or a formula of Al2O3.
Considering the definition of empirical formula, the correct answer is the second option: the empirical formula is Al₂O₃.
Definition of empirical formulaThe empirical formula is the simplest expression to represent a chemical compound, which indicates the elements that are present and the minimum proportion in whole numbers that exist between its atoms, that is, the subscripts of chemical formulas are reduced to the most integers. small as possible.
Empirical formula in this caseAssuming a 100 grams sample, the percentages match the grams in the sample. So you have 53 grams of Al and 47 grams of O.
Then it is possible to calculate the number of moles of each atom in the molecule, taking into account the corresponding molar mass:
Al: [tex]\frac{53 grams}{27 \frac{grams}{mole} }[/tex]= 1.9629 moles
O: [tex]\frac{47 grams}{16 \frac{grams}{mole} }[/tex]= 2.9375 moles
The empirical formula must be expressed using whole number relationships, for this the numbers of moles are divided by the smallest result of those obtained. In this case:
Al: [tex]\frac{1.9629 moles}{1.9629 moles}[/tex]= 1
O: [tex]\frac{2.9375 moles}{1.9629 moles}[/tex]≅ 1.5
You cannot have a decimal subscript, so you will multiply our answers by a factor of 2 to get to a whole number:
Al: 1× 2= 2
O: 1.5× 2= 3
Therefore the Al:O mole ratio is 2: 3
Finally, the correct answer is the second option: the empirical formula is Al₂O₃.
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Who kept scientific experiments from being performed in the middle
ages?
A. The Government
B. The Judicial System
C. The Board of Science
D. The Church
Answer:
D. The Church
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An electric range burner weighing 699.0 grams is turned off after reaching a temperature of 482.0°C, and is allowed to cool down to 22.7°C.
Calculate the specific heat of the burner if all the heat evolved from the burner is used to heat 560.0 grams of water from 22.7°C to 80.3°C.
J/g°C
Answer:
0.42 J/gºC
Explanation:
We'll begin by calculating the heat energy used to heat up the water. This can be obtained as follow:
Mass (M) of water = 560 g
Initial temperature (T₁) = 22.7 °C
Final temperature (T₂) = 80.3 °C.
Specific heat capacity (C) of water = 4.18 J/gºC
Heat (Q) absorbed =?
Q = MC(T₂ – T₁)
Q = 560 × 4.18 (80.3 – 22.7)
Q = 2340.8 × 57.6
Q = 134830.08 J
Finally, we shall determine the specific heat capacity of the burner. This can be obtained as follow:
Mass (M) of burner = 699 g
Initial temperature (T₁) = 482.0°C
Final temperature (T₂) = 22.7 °C
Heat (Q) evolved = – 134830.08 J
Specific heat capacity (C) of the burner =?
Q = MC(T₂ – T₁)
–134830.08 = 699 × C (22.7 – 482.0)
–134830.08 = 699 × C × –459.3
–134830.08 = –321050.7 × C
Divide both side by –321050.7
C = –134830.08 / –321050.7
C = 0.42 J/gºC
Therefore, the specific heat capacity of the burner is 0.42 J/gºC
During a lab experiment performed at STP conditions, you prepare HCl by reacting 100. ml of Cl2 gas with an excess of H2 gas.
How many ml of a solution of Ba(OH)2 0.230M do you need to neutralize all the HCl produced?
Answer:
19.4 mL Ba(OH)2
Explanation:
H2(g) + Cl2(g) --> 2HCl(aq) (make sure this equation is balanced first)
At STP, 1 mol gas = 22.4 L gas. Use this conversion factor to convert the 100. mL of Cl2 to moles.
0.100 L Cl2 • (1 mol / 22.4 L) = 0.00446 mol Cl2
Use the mole ratio of 2 mol HCl for every 1 mol Cl2 to find moles of HCl produced.
0.00446 mol Cl2 • (2 mol HCl / 1 mol Cl2) = 0.00892 mol HCl
HCl is a strong acid and Ba(OH)2 is a strong base so both will completely ionize to release H+ and OH- respectively. You need 0.00892 mol OH- to neutralize all of the HCl. Note that one mole of Ba(OH)2 contains 2 moles of OH-.
0.00892 mol OH- • (1 mol Ba(OH)2 / 2 mol OH-) • (1 L Ba(OH)2 / 0.230 M Ba(OH)2) = 0.0194 L = 19.4 mL Ba(OH)2
The first step in answering this reaction is to write down the required reaction equations and then answer the questions from stoichiometry(mass-mole relationship).
The first equation is;
[tex]H2(g) + Cl2(g) ------->2HCl(g)[/tex]
The second equation is
[tex]2HCl(g) + Ba(OH)2(aq) -------> BaCl2(aq) + 2H2O(l)[/tex]
From stoichiometry;
1ml = 1cm3
Since hydrogen is in excess, chlorine is the limiting reactant
1 mole of Cl2 occupies 22400cm3
x moles of Cl2 occupies 100cm3
x = 1 * 100/22400
x = 0.00446 moles of Cl2
According to the reaction equation;
1 mole of Cl2 yields 2 moles of HCl
0.00446 moles of Cl2 yields 0.00446 * 2/1
= 0.00892 moles of HCl
From the reaction equation;
2 moles of HCl reacts with 1 mole of Ba(OH)2
0.00892 moles of HCl reacts with 0.00892 * 1/2 = 0.00446 moles of Ba(OH)2
Since 0.00446 moles of Ba(OH)2 reacted
number of moles = concentration * volume
number of moles = 0.00446 moles
concentration = 0.230M
Let the volume in ml be V
0.00446 = 0.230 * V/1000
V = 0.00446 * 1000/ 0.230
V = 19.39 ml
Volume in ml = 19.39 ml of Ba(OH)2
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How can we find life on other planets?
Through satellites...
When the Sun and Moon are aligned in the same direction, the tides are higher than normal, known as________
Answer:
spring tides is the correct answer of your question
CH4 Structural formulas
Explanation:
Methane = CH4(formula)
How many atoms are in a ring made of pure gold, Au (element 79), if there are 0.092 moles of gold in it?
Answer:
i think it wil be 567489
Explanation:
ik im right :)
What resists pH change by reacting with acids and bases?
what is the pH level of soda?
Physical chemistry is the bridge between physics and chemistry.
a. True
b. False
Answer:
Im gonna go with.... B. False
________________________________
*rate this answer and say thanks please!
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Yes it is true. That physical chemistry is a bridge between physics and chemistry. Because here we study the physical behaviours of the chemical reactions.
Study the diagram of the two animals.
Which statement best describes the animals?
Animal X begins life as a tadpole, and animal Y begins life as a larva that looks like the adult.
Animal X begins life as a larva that looks like the adult, and animal Y begins life as a tadpole.
Both animal X and animal Y begin life as a tadpole and change form as they develop.
Both animal X and animal Y begin life as a larva that looks like the adult.
Both animal X and animal Y begin life as a tadpole and change form as they develop
Answer:
it is c, for those who want an answer fast
Explanation:
does anyone know the answer???
Answer:
ethyl ethernal
Explanation:
no explanation
The models show the phases of a substance at various temperatures. Which model BEST communicates the kinetic energy and particle arrangement of a liquid? A. Model D, because it has high kinetic energy so the particles in the model have ionized B. Model B, because it has some kinetic energy and the particles have a free flowing shape C. Model C, because it has high kinetic energy so the particles in the model have no definite shape D. Model A, because it has some kinetic energy and the particles move freely
Answer: Model B. I have included a graph for this question. Model D is incorrect because that is a model for plasma as liquid doesn't contain ionized particles. Model C is incorrect as that represents a solid. Model A is incorrect because that is showing a gas; the particles are moving very freely
According to the forces of attraction, model B communicates the kinetic energy and particle arrangement of a liquid.
What are forces of attraction?Forces of attraction is a force by which atoms in a molecule combine. it is basically an attractive force in nature. It can act between an ion and an atom as well.It varies for different states of matter that is solids, liquids and gases.
The forces of attraction are maximum in solids as the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.
The physical properties such as melting point, boiling point, density are all dependent on forces of attraction which exists in the substances.
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Your question is incomplete but most probably your full question was, The models show the phases of a substance at various temperatures. Which model BEST communicates the kinetic energy and particle arrangement of a liquid? A. Model D, because it has high kinetic energy so the particles in the model have ionized B. Model B, because it has some kinetic energy and the particles have a free flowing shape C. Model C, because it has high kinetic energy so the particles in the model have no definite shape D. Model A, because it has some kinetic energy and the particles move freely
how does someone get addicted to meth?
Joseph rides his bike for 30 miles in one hour
going west . Is it speed velocity or acceleration
Answer:
velocity
Explanation:
because he is going 30 miles west
How many moles are there in 8.0 grams of CaCO3
Answer: moles = 0.0799305403604264
Explanation:
what is the molar mass of aspartic acid
The molar mass of aspartic acid is 133.05g/mol.
What is molar mass?The molar mass is the mass per unit amount of substance of a given chemical entity. It is denoted by a symbol M. The SI unit of molar mass is kg/mol.
What is aspartic acid?Aspartic acid is one of the building-block of amino acids which is responsible for synthesizing proteins and regulating hormones in the human body.
The chemical formula of aspartic acid is C4H7NO4.
Atomic mass of C = 12.011u, H = 1.007u, N = 14.006u, O = 16u
Molar mass of C4H7NO4 = 4(12.011)+7(1)+14.006+4(16)
= 48.044+7+14.006+64
= 133.05g/mol
Hence, the molar mass of aspartic acid is 133.05g/mol.
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If 263 ml of a gas is collected at 47°c and 2.77 atm, what will the final temp be in C if the volume decreases to 195 mL and the pressure increases to 3.87 atm?
im stoopid so yeh pls help
Answer:
[tex]58.48^{\circ}\text{C}[/tex]
Explanation:
[tex]P_1[/tex] = Initial pressure = 2.77 atm
[tex]V_1[/tex] = Initial volume = 263 mL
[tex]T_1[/tex] = Initial temperature = [tex]47^{\circ}\text{C}=(47+273.15)\ \text{K}[/tex]
[tex]P_2[/tex] = Final pressure = 3.87 atm
[tex]V_2[/tex] = Final volume = 197 mL
[tex]T_2[/tex] = Final temperature
We have the relation
[tex]\dfrac{P_1V_1}{T_1}=\dfrac{P_2V_2}{T_2}\\\Rightarrow T_2=\dfrac{P_2V_2}{P_1V_1}\times T_1\\\Rightarrow T_2=\dfrac{3.87\times 195}{2.77\times 263}\times (47+273.15)\\\Rightarrow T_2=331.63\ \text{K}=331.63-273.15\\\Rightarrow T_2=58.48^{\circ}\text{C}[/tex]
The final temperature will be [tex]58.48^{\circ}\text{C}[/tex].
What is the molarity of a solution made by dissolving 5 mol of H3PO4 in 0.05 L of solution?
Need Fast!
Answer:
"100" is the molarity of solution.
Explanation:
The given values are:
Moles of solute,
= 5 mol
Liters of solution,
= 0.05 L
Now,
The molarity of a solution will be:
= [tex]\frac{Moles \ of \ solute}{Liters \ of \ solution}[/tex]
On substituting the values, we get
= [tex]\frac{5}{0.05}[/tex]
= [tex]100[/tex]
Question 7
3 pt:
N2 + 312 --> 2N13
If 81.3 grams of lodine is reacted with 4.49 grams of nitrogen what is the theoretical yield?
(Include the correct number of significant figures but no units)
Question 8
Answer:
84.3 g of nitrogen triiodide is the theoretical yield.
Explanation:
Hello there!
In this case, according to the chemical reaction:
[tex]N_2 + 3I_2 \rightarrow 2NI_3[/tex]
It is possible to compute the theoretical yield of nitrogen triiodide by each reactant via stoichiometry as shown below:
[tex]m_{NI_3}^{by\ N_2}=4.49gN_2*\frac{1molN_2}{28.01gN_2} *\frac{2molNI_3}{1molN_2}*\frac{394.72gNI_3}{1molNI_3} =126.55gNI_3\\\\m_{NI_3}^{by\ I_2}=81.3gI_2*\frac{1molI_2}{253.81gI_2} *\frac{2molNI_3}{3molI_2}*\frac{394.72gNI_3}{1molNI_3} =84.29gNI_3[/tex]
Therefore, we infer that the smallest amount is the correct theoretical yield as it comes from the limiting reactant, in this case, diatomic iodine as it yields 84.3 g (three significant figures) of nitrogen triiodide as the theoretical yield; incidentally, nitrogen acts as the excess reactant.
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Bonds are formed because atoms are more stable when they have the valence shell in the electron noble gas configuration (full outer valence shell). What is the net charge of either molecular
ionic compounds?
o
А
Positive
B
Negative
O &
D
Zero-neutral
Please Answer Giving Brainleist
What gas in the air is used by plants to make their own food?
A) Nitrogen
B) Water vapor
C) Carbon dioxide
D) Oxygen
Answer:
C) Carbon dioxide is the answer.
Answer:
C. Carbon Dioxide
Carbon is absorbed by plants and chemically converted to oxygen via photosynthsis.
Hope this helps!
A 16.4 g sample of calcium chloride is dissolved in enough water to make 750.0 mL of solution. Calculate the molarity of calcium chloride in this solution. plz help!!!
The molarity is an important method to calculate the concentration of a solution. The molarity of calcium chloride of 16.4 g in 750.0 mL of solution is 0.196 mol L⁻¹.
What is molarity?The molarity of a solution is defined as the number of moles of the solute present per litre of the solution. It is mainly employed in calculating the molarity of a binary solution. It is represented as 'M' and unit is mol L⁻¹.
The equation used to calculate the molarity is given as:
Molarity = Number of moles of the solute / Volume of the solution in litres
Molar mass of CaCl₂ = 110.98 g/mol
Given mass = 16.4 g
Number of moles = 16.4 / 110.98 = 0.147
750.0 mL = 0.75 L
Molarity = 0.147 / 0.75 = 0.196 mol L⁻¹
Thus the molarity is 0.196 mol L⁻¹.
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what is the electron configuration of S and Cl?
Answer:
S is [Ne] 3s²3p⁴
Cl is [Ne] 3s² 3p⁵
Explanation:
Balance the following equations:
C3H8 (g) + O2 (g) → CO2 (g) + H2O (g)
NH3 (g) O2 (g) NO2 (g) H2O (g)
Al(NO3) Na3S Al2S3 NaNO3
Explanation:
C3H8 + 502 ----> 3CO2 + 4H20
4NH3+7O2------> 4NO2+6H2O
2Al(NO3)3 + 3Na2S -------> Al2S3+6NaNO3
7) What is the speed of a jet plane
that flies 7200 km in 9.5 hours?
Answer:
68,400
Explanation:
Please please help me please please
Answer: 1. A, 2.B, 3. D, 4. B, 5. C
Explanation:
i have P.E. too lol have a great day!
What is the molarity of ZnCl, that forms when 20.0 g of zinc completely reacts with CuCl2, according to the following reaction? Assume a final
volume of 285 mL
Zn(s) + CuCl2(aq) → ZnCl2(aq) + Cu(s)