Answer:
3.
Explanation:
Hello,
In this case, considering the given number:
[tex]2.30x10^5[/tex]
We can see that it does not have zeros to left of the first nonzero digit which is 2, therefore, we just have to consider the 2, 3 and 0 as significant figures because the right-handed zeros are actually considered. Hence, such measurement has 3 significant figures.
A student is using a coffee-cup calorimeter to determine the enthalpy change of the endothermic reaction of two aqueous solutions. After both solutions are added to the cup, the student neglects to put the lid on the cup. This would cause the magnitude of the calculated ΔH° value to be: the answer is: too small, since the solution will absorb heat from the room. But why? Wouldn't depend on if the reaction releases or absorbs heat. Wouldn't it be too large because heat escapes the cup? I'm so confused
Answer:
See the answer below
Explanation:
First, it should be understood that an endothermic reaction is one that absorbs energy in the form of heat from the surrounding. The products of endothermic reactions usually have higher energy than their reactants. Hence, the ΔH° which is referred to as the enthalpy change is usually positive.
Forgetting to cover the coffee-cup calorimeter means some of the heat energy absorbed by the reactants would be exchanged back to the surroundings - a loss. It also means that the enthalpy change would be smaller compared to if the cup had been covered because some of the heat has been lost to the surrounding.
4-methyl-3-hexanol was prepared by reacting an alkene with either hydroboration-oxidation or oxymercuration-reduction. Draw the structure of the alkene that was used to prepare the alcohol in highest yield.
Answer:
Structure in attachment.
Explanation:
The oxymercuration-demercuration of an asymmetric alkene usually produces the Markovnikov orientation of an addition. The electrophile ⁺Hg(OAc), formed by the electrophile attack of the mercury ion, remains attached to least substituted group at the end of the double bond. This electrophile has a considerable amount of positive charge on its two carbon atoms, but there is more positive charge on the more substituted carbon atom, where it is more stable. The water attack occurs on this more electrophilic carbon, and the Markovnikov orientation occurs.
In hydroboration, borane adds to the double bond in one step. Boron is added to the less hindered and less substituted carbon, and hydrogen is added to the more substituted carbon. The electrophilic boron atom adds to the less substituted end of the double bond, positioning the positive charge (and the hydrogen atom) at the more substituted end. The result is a product with the anti-Markovnikov orientation.
A person tries to heat up her bath water by adding 5.0 L of water at 80°C to 60 L of water at 30°C. What is the final temperature of the water? Group of answer choices
Answer:[tex]T_f=33.85\°C[/tex]
Explanation:
Hello,
In this case, we can write the following relationship, explaining that the lost by the hot water is gained by the cold water:
[tex]Q_{hot,W}=-Q_{cold,W}[/tex]
Which in terms of mass, specific heat and temperatures, we have:
[tex]m_{hot,W}Cp_{W}(T_f-T_{hot,W})=-m_{cold,W}Cp_{W}(T_f-T_{cold,W})[/tex]
Whereas the specific heat of water is cancelled out to obtain the following temperature, considering that the density of water is 1 kg/L:
[tex]T_f=\frac{m_{hot,W}T_{hot,W}+m_{cold,W}T_{cold,W}}{m_{hot,W}+m_{cold,W}}\\\\T_f=\frac{5.0kg*80\°C+60kg*30\°C}{5.0kg+60kg} \\\\T_f=33.85\°C[/tex]
Regards.
Classify the chemical equations as being balanced or not balanced. CaO + 3C → CaC2 + CO Na + H2O → 2NaOH + H2 4Fe + O2 → 2Fe2O3 2Mg + O2 → 2MgO
Answer:
A) Balanced
B) Not Balanced
C) Not Balanced
D) Balanced
how are sound wave different from the waves in the sea or the ripples on water mark brainliest
Answer:
Sound wave are not solid nor liquid nor gas it is invisible and goes nearly through any thing.
While waters ripples are liquid which can be easily moved by anything
Use the periodic table to determine the number of valence electrons in each of the following elements.
Na:
E:
V:
Ar:
Answer:
Na: 1
F: 7
V: 5
Ar: 8
C: 4
Explanation:
The number of valence electrons by using periodic table are Na has 1, F has 7, V has 5, Ar has 8 and C has 4 valence electron.
What is periodic table ?The chemical elements are arranged in rows and columns in the periodic table, sometimes referred to as the periodic table of the elements. It is frequently used in physics, chemistry, and other sciences, and is frequently regarded as a symbol of chemistry.
Because of the orderly arrangement of the elements, it is known as the periodic table. They're arranged in rows and columns, as you'll see. Periods and groups are the names given to the horizontal rows and the vertical columns, respectively.
A system for arranging the chemical elements is the periodic table. The fundamental components of all matter are the chemical elements. The atomic number is a distinct characteristic of each chemical element. This figure is based on how many protons there are in each of the element's atoms.
Thus, The number of valence electrons by using periodic table are Na has 1, F has 7, V has 5, Ar has 8 and C has 4 valence electron.
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The idea that the moon, sun, and known planets orbit Earth is called the _______________ model of the universe.
Answer:
spherical model of the universe
For the reaction of hydrochloric acid and sodium thiosulfate, the rate law is written as:______
A. Rate = k [HCl]m [Na2S2O3]n
B. Rate = k [HCl + Na2S2O3]
C. Rate = t [HCl]a [Na2S2O3]x
D. Rate = t [HCl + Na2S2O3]
Answer:
A. [tex]Rate =k[HCl]^{m} [Na_2S_2O_3]^{n}[/tex]
Explanation:
Let's consider the reaction between hydrochloric acid and sodium thiosulfate.
2 HCl + Na₂S₂O₃ → H₂O + S + SO₂ + 2 NaCl
The rate law is:
[tex]Rate =k[HCl]^{m} [Na_2S_2O_3]^{n}[/tex]
where,
Rate is the reaction ratek is the rate constantm and n are the reaction orders, which can only be determined experimentally and may or not coincide with the stoichiometric coefficients.Abigail obtained 36.6 grams of calcium carbonate after performing a reaction. From her calculations, she knew she should have obtained 44.1 grams. What was her percent yield
Answer:
it would be 1
Explanation:
If Na was to form a 2 ion, from what orbital subshell would the second electron be lost?
Answer:
2p
Explanation:
Sodium has an atomic number of 11, thus, the neutral atom has 11 electrons. The electron configuration is:
Na: 1s² 2s² 2p⁶ 3s¹
To gain stability, it loses an electron from its outer shell to form the cation Na⁺. Its electron configuration is:
Na⁺: 1s² 2s² 2p⁶
If it were to lose a second electron to form a Na²⁺ cation, the electron should be lost from the 2p orbital subshell and its electron configuration would be:
Na²⁺: 1s² 2s² 2p⁵
6. Cross-cuts are best made with which of the following types of knife? A. Utility knife B. Scaler C. Paring knife D. Chef's knife
Answer:
A
Explanation:
Utility knife
Answer:
Utility knife
Explanation:
Which factor is least likely to cause a memory problem
How would you make a 30% ethanol solution?
Answer:
You need 30 ml of alcohol and 70 ml of water.
Explanation:
You want to end up with 100ml of liquid, 30% of which is alcohol. 30% of 100ml is 30/100 100 = 30 ml.
The SI prefix kilo- indicates _____.
A. hundred
B. thousand
C. hundredth
D. thousandth
Answer:
b
Explanation:
At an elevation where the boiling point of water is 93°C, 1.00 kg of water at 30°C absorbs 290.0 kJ from a mountain climber’s stove. Is this amount of thermal energy sufficient to heat the water to its boiling point? [cp of water = 4.18 J/(g · °C)] need more information to calculate can not be calculated even with more information no yes
Answer:
Yes, it will be enough.
Explanation:
We can calculate the heat (Q) required to heat 1.00 kg of water from 30°C to 93°C using the following expression.
Q = cp × m × ΔT
where,
cp: specific heat capacity of waterm: mass of waterΔT: change in the temperatureQ = cp × m × ΔT
Q = 4.18 J/g°C × 1.00 × 10³ g × (93°C-30°C)
Q = 263 kJ
Since 263 kJ are necessary, 290.0 kJ will be enough to heat the water.
The energy is sufficient to raise the temperature of the water to its boiling point.
We have the following information from the question;
Boiling point of water = 93°C
Mass of water = 1.00 kg or 1000 g
Heat capacity of water = 4.18 J/g · °C
Heat absorbed by water = 290.0 kJ or 290000 J
Initial temperature of the water = 30°C
Using the formula;
ΔH = mcθ
ΔH = Heat absorbed by the water
m = mass of the water
c = heat capacity of the water
θ = temperature rise (T2 - T1)
Substituting values;
290000 J = 1000 g × 4.18 J/g · °C (T2 - 30°C)
290000 = 4180T2 - 125400
T2 = 290000 + 125400/4180
T2 = 99.3°C
The energy is sufficient to raise the temperature of the water to its boiling point.
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If 25.0 g of NH₃ and 45.0g of O₂ react in the following reaction, what is the mass in grams of NO that will be formed? 4 NH₃ (g) + 5 O₂ (g) → 4 NO (g) + 6 H₂O (g)
Answer:
The correct answer would be : 33.8 g
Explanation:
Molar mass of ammonia,
Molar Mass = 1* Molar Mass(N) + 3* Molar Mass (H)
= 1*14.01 + 3*1.008 = 17.034 g/mol
mass(NH3)= 25.0 g (given)
number of mol of NH3,
n = mass of NH3/molar mass of NH3
=(25.0 g)/(17.034 g/mol)
= 1.468 mol
Now,
Molar mass of O2
= 32 g/mol
mass(O2)= 45.0 g
similar as ammonia
n (O2)=(45.0 g)/(32 g/mol)
= 1.406 mol
Balanced chemical equation is:
4 NH3 + 5 O2 ---> 4 NO + 6 H2O
1.83456 mol of O2 is required for 1.46765 mol of NH3
by the calculation we have only 1.40625 mol of O2
Thus, the limiting agent will be - O2
now the Molar mass of NO,
= 1*14.01 + 1*16.0
= 30.01 g/mol (similar formula used for NH3)
Balanced equation :
mol of NO formed = (4/5)* moles of O2
= (4/5)×1.40625 (from above calculation)
= 1.125 mol
mass of NO = number of moles × molar mass
= 1.125*30.01
= 33.8 g
Thus, the correct answer would be : 33.8 g
The amount of nitrogen oxide that can be formed in the given mass is 44.12 g.
The given parameters;
mass of ammonia, NH₃ = 25.0 gmass of oxygen, O₂ = 45.0 gThe reaction of the ammonia and oxygen is written as follows;
[tex]4NH_3(g) \ + \ 5O_2 (g) \ --> \ 4NO (g) \ + \ 6H_2O(g)\\\\[/tex]
Molar mass of NH₃ = (14) + (3 x 1) = 17 g/mol
Molar mass of NO = (14) + 16 = 30 g/mol
4(17 g/mol) of NH₃ ------------------ 4(30)
25 g/mol of NH₃ --------------------- ?
[tex]= \frac{4(30) \times 25}{4(17)} \\\\= 44.12 \ g[/tex]
Thus, the amount of nitrogen oxide that can be formed in the given mass is 44.12 g.
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Which of the following has the greatest electronegativity difference between the bonded atoms?
A) A strong acid made of hydrogen and a halogen, such as HCl
B) A diatomic gas, such as nitrogen (N2)
C) Cartoon bonded to a group 6A (16) nonmetal chalcogen, such as in Co
D) A group 1 alkali metal bonded to chloride, such as RbCl
Answer:
D) A group 1 alkali metal bonded to chloride, such as RbCl
Explanation:
Which of the following has the greatest electronegativity difference between the bonded atoms?
A) A strong acid made of hydrogen and a halogen, such as HCl
The electronegativity difference between H and Cl is:
ΔEN = |EN(H)-EN(Cl)| = |2.1-3.0| = 0.9
B) A diatomic gas, such as nitrogen (N₂)
The electronegativity difference between N and N is:
ΔEN = |EN(N)-EN(N)| = |3.0-3.0| = 0.0
C) Carbon bonded to a Group 6A (16) nonmetal chalcogen, such as in CO
The electronegativity difference between C and O is:
ΔEN = |EN(C)-EN(O)| = |2.5-3.5| = 1.0
D) A group 1 alkali metal bonded to chloride, such as RbCl
The electronegativity difference between Rb and Cl is:
ΔEN = |EN(Rb)-EN(Cl)| = |0.8-3.0| = 2.2
Determine whether or not the mixing of each of the two solutions indicated below will result in a buffer.
A. 75.0 mL of 0.10 MHF; 55.0 mL of 0.15 MNaF
B. 150.0 mL of 0.10 MHF; 135.0 mL of 0.175 MHCl
C. 165.0 mL of 0.10 MHF; 135.0 mL of 0.050 MKOH
D. 125.0 mL of 0.15 M CH3NH2; 120.0 mL of 0.25 MCH3NH3Cl
E. 105.0 mL of 0.15 M CH3NH2; 95.0 mL of 0.10 M HCl
A buffer is a solution that mitigates against changes in acidity/alkalinity.
A buffer consists of a weak acid and its conjugate base. Also, a buffer can be formed from a weak base and its conjugate acid. A buffer is a solution that helps to mitigate against changes in acidity and alkalinity.
Let us now examine the solution mixtures listed in the question:
75.0 mL of 0.10 MHF; 55.0 mL of 0.15 MNaF. This can work as a buffer solution because it contains a weak acid (HF) and its conjugate base(F^-).150.0 mL of 0.10 MHF; 135.0 mL of 0.175 MHCl will not function as a buffer solution 165.0 mL of 0.10 MHF; 135.0 mL of 0.050 MKOH will not function as a buffer solution125.0 mL of 0.15 M CH3NH2; 120.0 mL of 0.25 MCH3NH3Cl will not function as a buffer solution105.0 mL of 0.15 M CH3NH2; 95.0 mL of 0.10 M HCl will not function as a buffer solution.Learn more: https://brainly.com/question/13439771
how many moles of MgO are produced when .250 mol of Mg reacts completely with O2
Answer:
0.250 mol
Explanation:
The reaction between Mg and O2 is given by;
2Mg + O2 --> 2MgO
From the equation above; 2 moles of Mg reacts to form 2 moles of MgO.
0.250 mol of Mg would produce x mol of MgO.
2 = 2
0.250 = x
x = 0.250 * 2/2 = 0.250 mol
A concentration cell is one in which both the anode and cathode are the same but with different concentrations. Calculate the cell potential with [Zn2+] = 0.10 M[Zn2+] = 0.10 M for the cathode and the [Zn2+] = 0.010 M[Zn2+] = 0.010 M for the anode?
Answer: 0.029 V
Explanation:
For the given chemical reaction :
[tex]Zn^{2+}(0.10M)(aq)+Zn(s)\rightarrow Zn^2+{0.010M)(aq)+Zn(s)[/tex]
Using Nernst equation :
[tex]E_{cell}=E^0_{cell}-\frac{2.303RT}{nF}\log\frac{\text {anodic ion concentration}}{\text {cathodic ion concentration}}[/tex]
where,
F = Faraday constant = 96500 C
R = gas constant = 8.314 J/mol.K
T = room temperature = 298 K
n = number of electrons in oxidation-reduction reaction = 2
[tex]E^0_{cell}[/tex] = standard electrode potential of the cell = 0 (as both metals are same )
[tex]E_{cell}[/tex] = emf of the cell = ?
[tex]E_{cell}=0-\frac{2.303\times 8.314\times 298}{2\times 96500}\log\frac{0.010}{0.10}[/tex]
[tex]E_{cell}=0.029V[/tex]
Thus the cell potential will be 0.029 V
When converting 3.45 pounds to grams you need to know that 1 pound is equal to 453.6 grams. What would go on the bottom (denominator) of the first conversion factor? *
Answer:
it would be 3.45lb/1 *454grams /lb
Explanation:
Put the following in order from least to most dense. Water, steam, salt water, ice
A substance formed in a chemical reaction is called a
O A. reactant
B. equation
C. None of these
D. product
Answer: Product
Explanation:
A substance formed in a chemical reaction is called a products ,therefore option (d) is correct .
What do you mean by the chemical reaction ?A chemical reaction is a process that occurs when two or more molecules interact to form a new product(s).
Compounds that interact to produce new compounds are called reactants whereas the newly formed compounds are called products.
Products are substances that are created as a result of a chemical reaction. These products of reactions may be ions or molecules.
The result of a chemical reaction might exist in the solid, liquid, or gaseous phases.
A + B → C + D
Here,
A and B are the reactants, and
C and D are the products of their reaction.
A substance formed in a chemical reaction is called a products ,hence option (d) is correct .
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Which of these species would you expect to have the highest standard entropy (S°)?
a. CH4(g)
b. C2H2(g)
c. C2H4(g)
d. C2H6(g)
e. C3H8(g)
Answer:
e. C₃H₈(g)
Explanation:
Standard entropy is the absolute entropy of a substance at 1 atm and 25°C.
For different substances in the same phase, molecular complexity determines which ones have higher entropies.
Consider the gases CH₄, C₂H₂, C₂H₄, C₂H₆, C₃H₈. Propane (C₃H₈) has a more complex structure and hence more ways to execute molecular motions, which also increase its microstates. Therefore, propane has the greatest standard entropy.
The standard entropy of propane has been highest among the given molecules. Thus, option E is correct.
The standard entropy has been the energy possessed by the 1 mole of a pure substance at standard pressure and temperature.
The entropy has been proportional to the molecular weight and structure complexity. The molecule with higher molecular weight and structure complexity tends to have higher entropy.
In the given set of molecules, the molecular mass and structure complexity of propane has been the highest. Thus, the standard entropy of propane has been highest among the given molecules. Option E is correct.
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once energy is applyied to cause a object to vibrate a sound occours
Answer:
its true
Explanation:
Answer:
true
Explanation:
you stop on ground, ground vibrates and makes sound
How many atoms are represented by one formula unit of aluminum chromate, Al2(CrO4)3
Answer:
17 atoms
Explanation:
If what we want is to calculate the number of atoms. We must take into account the subscripts of the formula. We can rewrite the formula taking into account the "ones" implicit in the formula, therefore we will have:
[tex]Al_2(Cr_1O_4)_3 [/tex]
Now we have a "3" outside the parenthesis. Therefore, we must multiply this 3 by the number of atoms within the parentheses:
-) Oxygen atoms: 4 x 3 = 12 atoms
-) Chromium atoms: 1 x 3 = 3 atoms.
If we take into account we have 2 aluminum atoms, in total, we will have:
-) 12 oxygen atoms
-) 3 chromium atoms
-) 2 aluminum atoms
12 + 3 + 2 = 17 atoms
In total, we will have 17 atoms.
See figure 1
I hope it helps!
Barium chloride and sodium sulfate react according to the following equation. BaCl 2 + Na 2SO 4 → BaSO 4 + 2NaCl Answer the following question(s) about this reaction. How many grams of barium chloride are needed to make 100. grams of barium sulfate?
According to the stoichiometry and the given balanced chemical equation 89.22 g of barium chloride are needed to make 100 grams of barium sulfate.
What is stoichiometry?Stoichiometry is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.
Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.
In the given chemical equation, 208.23 g of barium chloride produces 233.38 g of barium sulfate ,so for 100 g of barium sulfate 208.23×100/233.38 =89.22 g of barium chloride is required.
Thus, 89.22 g of barium chloride are needed to make 100 grams of barium sulfate.
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A 175.3 mg sample of C10H12O2 was dissolved in 1.50 g of chloroform (Kb = 3.63 °C/m). What is the boiling point of this solution.
Answer:
[tex]Tb=63.8\°C[/tex]
Explanation:
Hello,
In this case, for the boiling point elevation, we have:
[tex]\Delta T=i*m*Kb[/tex]
Whereas the van't Hoff factor for the given substance is 1 since is not ionizing. Moreover, the molality is computed by:
[tex]m=\frac{mol_{solute}}{m_{solvent}}=\frac{175.3mg*\frac{1g}{1000mg}*\frac{1nol}{164g} }{1.50g*\frac{1kg}{1000g} } =0.713m[/tex]
In such a way, since the boiling point of pure chloroform is 61.2 °C, the boiling point of the solution is:
[tex]Tb=61.2\°C+1*0.713m*3.63\frac{\°C}{m} \\\\Tb=63.8\°C[/tex]
Regards.
In the Lewis structure for ICl2–, how many lone pairs of electrons are around the central iodine atom?
a. 0
b. 1
c. 2
d. 3
e. 4
Answer:
where is rhe structure
The components that a cell can contain are (check all that apply)
Answer:
The components that a cell can contain are
nucleuscell membraneCytoplasmvacuolecell wall