Answer:
B) 82 protons
Explanation:
The number of protons for an element never change. 82 Is the atomic number for Pb which is how many protons it has. An isotope means it has more neutrons.
1. The atomic symbol of aluminum is written as 2713Al. What information do you get from it?
Answer:
its mass number and atomic number
Explanation:
atlmic number(subscript)=13
mass number(superscript)=27
Na-23 has 12 neutrons. What is it’s atomic number?
Answer:
11
Explanation:
Data obtained from the question include:
Mass number = 23
Neutron = 12
Atomic number =.?
Next, we shall determine the number of protons present in the element.
This can be achieved by doing the following:
Mass number = Proton + Neutron
Mass number = 23
Neutron = 12
Proton =...?
Mass number = Proton + Neutron
23 = Proton + 12
Collect like terms
Proton = 23 – 12
Proton = 11
The atomic number of an element is equal to the proton number.
Atomic number = proton number
Proton number = 11
Atomic number = proton = 11
Therefore, the atomic number is 11.
)Assertion: Corrosion is a beneficial process for metals. Reason : Galvanising and electroplating of metals prevent corrosion.
What is the precipitate in the following reaction?
2AgNO3(aq) + Na2S(aq) → Ag2S(s) + 2NaNO3(aq)
Answer:
2Ag(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(aq)
Explanation:
The final equation is
2Ag(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(aq)
2Ag(+1)NO3(-1)(aq) + Na2(+1)S(-2)(aq) --> Ag2(+1)S(-2)(s) + 2Na(+1)NO3(-1)(aq)
AgNO3, Na2S, and NaNO3 are all strong electrolytes, so we immediately separate those, making the new equation:
2Ag(+1)(aq) + 2NO3(-1)(aq) + 2Na(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(s) + 2Na(+1)(aq) + 2NO3(-1)(aq)
After that, you cancel out all the ions that appear more than once, which in this case would leave us with a final equation of...
2Ag(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(aq)
Answer:
Explanation:
C
Earth’s outermost layer is separated into a dozen or more large and small slabs, called _______. A. continental crust B. tectonic plates C. granite slabs D. Pangea
Answer:
Tectonic Plates
Explanation:
Answer:
Tectonic plates
Explanation:
A 36.0−g sample of an unknown metal at 99°C was placed in a constant-pressure calorimeter containing 70.0 g of water at 24.0°C. The final temperature of the system was found to be 28.4°C. Calculate the specific heat of the metal. (The heat capacity of the calorimeter is 12.4 J/°C.)
Answer: 0.52849 j /g °C
Explanation:
Given the following :
Mass of metal = 36g
Δ Temperature of metal = (28.4 - 99)°C = - 70.6°C
Mass of water = 70g
Δ in temperature of water = (28.4 - 24.0) = 4.4°C
Heat lost by metal = (heat gained by water + heat gained by calorimeter)
Quantity of heat(q) = mcΔT
Where; m = mass of object ; c = specific heat capacity of object
Heat lost by metal:
- (36 × c × - 70.6) = 2541.6c - - - - (1)
Heta gained by water and calorimeter :
(70 × 4.184 × 4.4) + (12.4 × 4.4) = 1288.672 + 54.56 = 1343.232 - - - - (2)
Equating (1) and (2)
2541.6c = 1343.232
c = 1343.232 / 2541.6
c = 0.52849 j /g °C
Name the layer where the pressure is 3.5 million atmospheres:
Answer:
The Inner Core
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What shape is represented by three bound groups and one lone pair around a
central atom?
A. Bent
B. Tetrahedral
C. Linear
D. Trigonal pyramidal
Answer:
D Trigonal pyramidal
Explanation went over in class:
Answer:
D. Trigonal pyramidal
Explanation:
A P E X !
The steady state vital to life is possible because:________
a. the cell cannot convert energy from one form to another.
b. all cells are autotrophic.
c. all reactions are exothermic.
d. the cell continually takes up energy from the environment.
e. all reactions are at equilibrium.
Answer: The correct answer is e) all reactions are at equilibrium.
Explanation: In order for cellular vitality to develop, it is necessary for it to be in energetic balance with the environment, that is, to give and receive energy with the environment that surrounds it through endothermic or exothermic reactions. That is why the development of life is considered a system that constantly exchanges with the environment. In turn, that the cell unit maintains a balance with the environment causes homeostasis to occur among the whole organism.
Ethylene, a gas found in nature, is commonly used to ripen bananas and other fruits. Which compound is ethylene?
H2C — CH2
НО
НО
Н
Н
0
С — С
Н
Н
ОН — СЕ С — Н
Answer:
C2H4
Explanation:
cause the compound of ethylene is C2H4
Ethylene is a hydrocarbon gas with the chemical formula C₂H₄. It is a simple molecule that consists of two carbon atoms and four hydrogen atoms and is also known as ethene. The skeletal structure is CH₂=CH₂.
What is ethylene ?Ethylene is a colorless and odorless gas that is the simplest member of the olefin class of hydrocarbons, with the chemical formula C₂H₄. It is an important organic compound and is widely used in industry.
Ethylene is primarily used to produce polyethylene, which is one of the most common plastic materials in the world. It is also used as a fuel in some industrial processes, as a refrigerant, and as a precursor to other chemicals.
It is an important plant hormone and is involved in various physiological processes such as fruit ripening, senescence, and abscission. Ethylene is naturally produced by plants, but it can also be produced artificially and is commonly used in agriculture to ripen fruits and vegetables.
Thus, the ethylene compound is CH₂=CH₂.
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how many sigma and pi bonds in propionic bond
what is an electrolyte? the fastest answer will get bainliest.
Answer:
Electrolytes are substances which undergo chemical change when electricity is passed through them.
how to make a salt by neutralization reaction
Answer:
Acid+Base=Salt+water
This is the formula of neutralization reaction.
According to this formula you can make salts by reacting an acid with a base.
Hope this helps ❤❤❤.
D Serum Levels Of 4 Mcg/mL, Calculate The Dose, In Milligrams, For A 120-lb Patient That May Be Expected To Result In A Blood Serum Gentamicin Level Of 4.5 Mcg/mL. This problem has been solved! See the answer If the administration of gentamicin at a dose of 1.75 mg/kg is determined to result in peak blood serum levels of 4 mcg/mL, calculate the dose, in milligrams, for a 120-lb patient that may be expected to result in a blood serum gentamicin level of 4.5 mcg/mL.
Answer:
The patient requires a dose of 107.2 mg of gentamicin
Explanation:
A dosage of 1.75 mg per Kilogram body weight results in blood serum levels of 4.5 mcg/mL
This means that; 1.75 mg/ kg = 4.0 mcg/mL
Therefore, dosage of gentamicin in mg/kg that will result in 4.5 mcg/mL blood serum level = (1.75 mg/Kg * 4.5 mcg/mL) / 4.0 mcg/mL
Dosageof gentamicin = 1.97 mg/Kg
1-lb = 0.453592 Kg
Weight of 120-lb patient in Kg = 120 * 0.453592 = 54.43 Kg
Dose in mg required by patient = 1.97 mg/Kg * 54.43 Kg = 107.2 mg
Therefore, the 120-lb patient requires a dose of 107.2 mg of gentamicin to result in a blood serum level of 4.5 mcg/mL
what’s the reaction type of aqueous magnesium sulfate + aqueous sodium carbonate?
Answer: Double displacement reaction
Explanation:
Double displacement reaction is defined as the reaction where exchange of ions takes place.
The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
The chemical reaction between aqueous magnesium sulfate and aqueous sodium carbonate is represented as:
[tex]MgSO_4(aq)+Na_2CO_3(aq)\rightarrow Na_2SO_4(aq)+MgCO_3(s)[/tex]
In which particle model are the red and blue particles MOST LIKELY to bump into each other? PLEASE HELP WILL MARK BRAINLIEST!!
Answer:
441
Explanation:
In particle model A are the red and blue particles MOST LIKELY to bump into each other and the correct option is option A.
What is Particle Model of Matter?The particle model of matter is a theory that explains how the particles that make up a substance are arranged, and how they move and interact with each other.
The particle model explains the properties of solids, liquids and gases. The particle model can explain changes of state.
Particles of matter have spaces between them. Atoms and molecules have spaces between them. In a gas, there are large spaces between them. In a a liquid they are closer together. In a solid, the particles are packed close enough together they can hardly move.
Therefore, In particle model A are the red and blue particles MOST LIKELY to bump into each other and the correct option is option A.
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A student has a piece of aluminum metal what is the most reasonable assumption a student can make about the metal
Answer:
- It could be stretched into a thin wire.Explanation:
As per the question, the most rational claim that the student can make about the aluminum metal is that 'it could be stretched into a thin wire' without breaking which shows its ductility. It is one of the most significant characteristics of a metal. Metals can conduct electricity in any state and not only when melted. Thus, option A is wrong. Options C and D are incorrect as metals neither have the same shape always nor do they break on hitting with a hammer. Therefore, option E is the correct answer.
Answer:
Yes, the other person is correct; the answer is E. It could be stretched into a thin wire.
Explanation:
Here is why it is NOT B:
"A briskly burning wood fire is plenty hot enough to melt aluminum. If it's just smoldering (like a lot of campfires) it won't create enough heat to melt aluminum."
Therefore, CAMPFIRES are not likely to melt aluminum if it is thrown in. Aluminum's melting point is 1,221 ° F. Typical campfires are about 900 ° F.
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2g of magnesium Oreo to excess dilute acid according to the equation Mg(s) + 2H (aq) --- Mg² (aq) + H2 (g) (Realitive atomic mass of Mg= 24, molar mass volume at room temperature and pressure = 24dm³) The volume of hydrogen, measured at room temperature I pressure, that is produced is A) 1000 cm³ B)1500 cm³ C) 2000 ³cm D) 24 000 cm³
Answer:
Option C. 2000 cm³.
Explanation:
We'll begin by calculating the number of mole in 2 g of Mg. This is illustrated below:
Molar mass of Mg = 24 g/mol
Mass of Mg = 2 g
Mole of Mg =?
Mole = mass /Molar mass
Mole of Mg = 2/24
Mole of Mg = 8.33×10¯² mole.
Next, we shall determine the number of mole of H2 produced from the reaction. This is illustrated below:
Mg(s) + 2H^+ (aq) —› Mg^2+(aq) + H2 (g)
From the balanced equation above,
1 mole of Mg reacted to produce 1 mole of H2.
Therefore, 8.33×10¯² mole of Mg will also produce 8.33×10¯² mole of H2.
Finally, we shall determine the volume of H2 produced. This is illustrated below:
1 mole of H2 occupy 24000 cm³ at room temperature and pressure.
Therefore, 8.33×10¯² mole of H2 will occupy = 8.33×10¯² x 24000 ≈ 2000 cm³ at room temperature and pressure.
Therefore, 2000 cm³ of H2 were obtained from the reaction.
HELPSS!
Isopropyl alcohol has a density of 0.785g/ml at 25°C. How much is contained in a 150ml sample of this alcohol?
Answer:
The amount of isopropyl alcohol contained in 150 ml of the solution is 117.15 grams
Explanation:
The density of a substance is the mass per unit volume, therefore, we have;
The density of the isopropyl alcohol = 0.785 g/ml at 25°C
The density = mass/volume
Mass = Density × Volume
The mass of the 150 ml of isopropyl alcohol is therefore;
Mass = 0.785 g/ml × 150 ml = 117.15 g
The amount in grams contained in 150 ml of sample = 117.15 g.
To what temperature should 2.3L of a gas at 25degree Celsius be heated in order to expand its volume to 4 L under constant pressure
Answer:
518.52K
Explanation:
Charles law, which describes the direct relationship between the volume and the temperature of a gas when the pressure is constant, will be used for this question. The Charles law equation is:
V1/T1 = V2/T2
Where; V1 is the volume of the gas at an initial state (Litres)
T1 is the absolute temperature of the gas at an initial state (Kelvin)
V2 is the volume of the gas at a final state (Litres)
T2 is the absolute temperature of the gas at a final state (Kelvin)
According to the question, V1 = 2.3L, T1 = 25°C, V2 = 4L, T2 = ?
We need to convert the temperature to the absolute temperature unit in Kelvin (K) i.e.
T(K) = T(°C) + 273.15
T(K) = 25°C + 273.15
T1 (K) = 298.15K
To find for T2 in the equation, we make T2 the subject of the formula:
T2 = V2 × T1 / V1
T2 = 4 × 298.15 / 2.3
T2 = 1192.6/2.3
T2 = 518.52
Thus, the temperature must be heated to 518.52K in order to expand to a volume of 4L. This answer is in accordance to Charles law that the volume increases with increase in temperature and vice versa.
according to Bohr atomic model
Answer:
A small positively charged nucleus surrounded by revolving negatively charged electrons in fixed orbits
What type of reaction is: ammonium nitrate -> dinitrogen monoxide + water?
Answer:
The thermal decomposition of ammonium nitrate to produce dinitrogen monoxide and water. This reaction takes place at a temperature of 200-260°C.
List at least four characteristics of acids
Answer:
pH>7
sour taste
donate H+ ions
turn litmus paper from blue to red
Explanation:
Answer:
Explanation:
pH < 7.
Sour taste (though you should never use this characteristic to identify an acid in the lab)
Reacts with a metal to form hydrogen gas.
Increases the H+ concentration in water.
Donates H+ ions.
Turns blue litmus indicator red.
what kind of a compounds act as an electrolyte? explain with and example
Answer:
ionic compounds
Explanation:
just finished ap chem
Answer:
An ionic compound can act as an electrolyte. This is because an electrolyte should allow charges to travel inside it.
e.g = H2SO4, NaCl
Explanation:
1) Determine a fórmula da base hidróxido de bário: * 1 ponto a) b) c) d) 2) As bases são substâncias iônicas, ou seja, quando são solubilizadas em água liberam íons, qual das características abaixo pode ser atribuída as soluções iônicas? * 1 ponto a) Conduzem corrente elétrica. B) Isolantes elétricos. C) Radioatividade. D) Emissão de raio UVA.
Answer:
1) Ba(OH)₂
2) The correct option is a) they conduct electricity.
Explanation:
To deduce the formula of Barium hydroxide, we have to go to the periodic table and look for the Barium (Ba), which is in group 2 and has an ionic charge of 2+. Hydroxides are not an element that is present in the periodic table is the combination of Oxygen and Hydrogen (OH), and its ionic charge is 1-.
To name this substance, we write the elements that form it, which are Ba OH, then we see the ionic charges that they have, Ba2+ OH 1- and we change these charges giving the 2+ to the OH and the 1- to the Ba. It would look Ba OH₂; we do not write the 1, and as there is a 2, the OH, has to be between brackets so that the final formula is Ba(OH)₂. What we did is balancing the charges of the elements. In other words, we need 2 OH for every Ba. Hydroxides give an electron to balance the Ba ionic charge.
Barium Hydroxide is an ionic compound because ionic compounds are formed by a metal (Ba) and a nonmetal element (OH), ionic compounds are charged, so when they are in an aqueous solution they conduct electricity because their ions move freely in the solution.
In calculating the equilibrium constant for a reaction, the coefficients of the chemical equation are used as exponents for the factors in the equilibrium expression. TRUE FALSE
Answer: The given statement is TRUE.
Explanation:
An equilibrium reaction is one in which rate of forward reaction is equal to the rate of backward reaction.
Equilibrium constant is defined as the ratio of the product of the concentration of products to the product of the concentration of reactants each raised to their stochiometric coefficient.
For example for the given equilibrium reaction;
[tex]2H_2O(g)\leftrightharpoons 2H_2(g)+O_2(g)[/tex]
[tex]K_{eq}=\frac{[H_2]^2[O_2]}{[H_2O]^2}[/tex]
Thus the given statement that in calculating the equilibrium constant for a reaction, the coefficients of the chemical equation are used as exponents for the factors in the equilibrium expression is True.
Give two reasons why mixing and heating sulphur powder and iron filings on a watch glass is chemical change
Answer:
When iron filings and sulphur powder are mixed and heated they undergo a chemical reaction and form ferrous sulphide (FeS). It is a new substance which has properties entirely different from Fe and S. Therefore, heating of mixture of iron and sulphur powder is a chemical change.
Which of these elements have the smallest 1st ionization energy
Answer:
Ionization energy increases as you go across a period, and increases as you move up a group. So, elements with the smallest ionization energy would be at the bottom left corner of the periodic table. Examples of elements with small ionization energy: Francium (Fr), Cesium (Cs), Radium (Ra).
Potassium hydrogen tartrate is an acid used in making cookies such as snicker doodles. (In your home, it is called cream of tartar.) It can be titrated with a base such as KOH to determine purity. A sample of 0.500 g is titrated to a pink endpoint with 21.58 mL of 0.1125 M KOH. Determine the percentage of potassium hydrogen tartrate (KHC4H4O6) in the sample. The acid/base ratio is 1:1.
Answer:
91.4%
Explanation:
Potassium hydrogen tartrate, KHT, reacts with KOH as follows.
KHT + KOH → H₂O + K₂T
where 1 mole of acid (KHT) reacts per mole o base (KOH), -That is acid/base ratio 1:1
The endpoint of a titration is the point in which moles of KOH = moles of KHT, you can see this endpoint with an indicator or doing a potentiometric titration.
As the endpoint requires 21.58mL = 0.02158L of a 0.1125M KOH, moles of KOH = moles of KHT are:
0.02158L × (0.1125mol / L) = 2.428x10⁻³ moles of KOH = moles of KHT
To convert these moles to grams you use molar mass of KHT (188.177g/mol):
2.428x10⁻³ moles of KHT × (188.177g / mol) = 0.457g of KHT are in the sample.
As you add 0.500g of sample, percentage of KHT in the sample is:
(0.457g / 0.500g) × 100 =
91.4%-That is the purity of the sample-
What is the total energy change for the following reaction:CO+H2O-CO2+H2
Answer:
[tex]\large \boxed{\text{-41.2 kJ/mol}}[/tex]
Explanation:
Balanced equation: CO(g) + H₂O(g) ⟶ CO₂(g) + H₂(g)
We can calculate the enthalpy change of a reaction by using the enthalpies of formation of reactants and products
[tex]\Delta_{\text{rxn}}H^{\circ} = \sum \left( \Delta_{\text{f}} H^{\circ} \text{products}\right) - \sum \left (\Delta_{\text{f}}H^{\circ} \text{reactants} \right)[/tex]
(a) Enthalpies of formation of reactants and products
[tex]\begin{array}{cc}\textbf{Substance} & \textbf{$\Delta_{\text{f}}$H/(kJ/mol}) \\\text{CO(g)} & -110.5 \\\text{H$_{2}$O} & -241.8\\\text{CO$_{2}$(g)} & -393.5 \\\text{H$_{2}$(g)} & 0 \\\end{array}[/tex]
(b) Total enthalpies of reactants and products
[tex]\begin{array}{ccr}\textbf{Substance} & \textbf{Contribution)/(kJ/mol})&\textbf{Sum} \\\text{CO(g)} & -110.5& -110.5 \\\text{H$_{2}$O(g)} &-241.8& -241.8\\\textbf{Total}&\textbf{for reactants} &\mathbf{ -352.3}\\&&\\\text{CO}_{2}(g) & -393.5&-393.5 \\\text{H}_{2} & 0 & 0\\\textbf{Total}&\textbf{for products} & \mathbf{-393.5}\end{array}[/tex]
(c) Enthalpy of reaction [tex]\Delta_{\text{rxn}}H^{\circ} = \sum \left( \Delta_{\text{f}} H^{\circ} \text{products}\right) - \sum \left (\Delta_{\text{f}}H^{\circ} \text{reactants} \right)= \text{-393.5 kJ/mol - (-352.3 kJ/mol}\\= \text{-393.5 kJ/mol + 352.3 kJ/mol} = \textbf{-41.2 kJ/mol}\\ \text{The total enthalpy change is $\large \boxed{\textbf{-41.2 kJ/mol}}$}[/tex]