Answer:
1. A compound is a group of elements that cannot be separated by physical methods.
NaCl is a compound becuse it cannot be separated by physical methods.
It consists of postive and negative ions.
It can be separated only by chemical reactions.
2. (a) A is a mixture of iron and sulphur and it is in liq form.
(b) Gas B is hydrogen gas and it has sharp pungent irritating smell.
(c) It is a physical change.
Explanation:
How can the rate constant be determined from the rate law
Answer: The rate constant is the reaction rate divided by the concentration terms.
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.
Suppose you carry out a titration involving 3.00 molar HCl and an unknown concentration of KOH. To bring the reaction to its end point, you add 35.3 milliliters of HCl to 105.0 milliliters of KOH. What is the concentration of the KOH solution?
Answer: The concentration of the KOH solution is 1.01 M
Explanation:
According to neutralization law:
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1[/tex] = basicity of [tex]HCl[/tex] = 1
[tex]n_2[/tex] = acidity of KOH = 1
[tex]M_1[/tex] = concentration of HCl = 3.00 M
[tex]M_2[/tex] = concentration of KOH = ?
[tex]V_1[/tex] = volume of HCl = 35.3 ml
[tex]V_2[/tex] = volume of KOH = 105.0 ml
Putting the values we get:
[tex]1\times 3.00\times 35.3=1\times M_2\times 105.0[/tex]
[tex]M_2=1.01[/tex]
Thus the concentration of the KOH solution is 1.01 M
What is the concentration of a solution if 65 g of sugar is dissolved into 200 ml of water?
Answer: the concentration in g/L 325 while in molarity is 0.6398(M).
Answer:
325 g/L,
0.9503 M
Explanation:
65 g sugar --- 0.2 L
x g --- 1 L
x = 65/0.2 g/L = 325 g/L
Sugar(sucrose) is C12H22O11.
Molar mass (C12H22O11) = 12*12 + 1*22 + 16*11 = 342 g/mol
325 g/L * 1 mol/342 g = 0.9503 mol/L = 0.9503 M
Answer 0.6398(M) is not related to sugar (sucrose),
it should be given formula or molar mass of sugar if it is different than sucrose.
144g of KCl dissolved in 1000cm3of water at 90oC. Calculate the solubility of KCl at this temperature. (K=39, Cl=35.5, 1dm3=1000cm3).
Answer:
The solubility of KCl is 1.93 mol/dm³
Explanation:
The information given are;
The mass of the potassium chloride, KCl = 144 g
The volume of the water solvent = 1000 cm³ = 1 dm³
The temperature of the solvent = 90 °C
The atomic mass of potassium, K = 39 u
The atomic mass of chlorine, Cl = 35.5 u
The number of moles of potassium in one mole of potassium chloride, KCl = 1 mole
The number of moles of chlorine in one mole of potassium chloride, KCl = 1 mole
The molar mass of the potassium chloride = 39 + 35.5 = 74.5 g/mol
The number of moles, n, of potassium chloride, KCl in 144 g of potassium chloride, KCl is given as follows
n = Mass/(Molar mass) = 144/74.5 = 1.93 moles
1.93 moles will dissolve in 1 dm³
Therefore, the solubility of KCl is 1.93 mol/dm³.
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.
Why do group 12 elements have different properties than group 13 elements
Answer:
A
Explanation:
Which condition must be met in order for an equation to be balanced? The elements in the reactants are the same as the elements in the products. There are fewer elements in the reactants than there are in the products. The number of atoms in the reactants is greater than the number of atoms in the products. The number of atoms in the reactants equals the number of atoms in the products.
Answer:
The number of atoms in the reactants equals the number of atoms in the products.
Explanation:
In every chemical reaction equation there are two sides; the reactants sides and the products side. The reactants side shows the species that combine to form the products. On both sides of the reaction equation, chemical species are found to be composed of atoms.
The major principle in balancing of chemical reaction equations is that the number of atoms of each element in the reactants side must be equal to the number of atoms of the same element on the products side. Once this condition is achieved, we can now say that the chemical equation is balanced.
Answer:
Answer D: The number of atoms in the reactants equals the number of atoms in the products.
Explanation:
Had the answer plus doing the quiz right now and got it right 100%
Answer the following questions: On a 10-fold dilution of a weak acid, the pH will ______________ . On a 10-fold dilution of a weak base, the pH will ______________. If one adds a very small amount of strong base to a buffered solution, the pH will _______________. Can you make a buffer using a strong acid
Answer:
i) increase
ii) decrease
iii) remain the same
iv) No, because it dissociates completely.
Explanation:
On a 10-fold dilution of a weak acid, the pH will increase because the concentration of hydrogen ions will decrease thereby increasing the pH to close to that of water.
On a 10-fold dilution of a weak base, the pH will decrease due to the removal of hydroxide ions from the solution. This results in the solution having a H closer to that of water.
If one adds a very small amount of strong base to a buffered solution, the pH will remain constant because a buffer solution acts to withstand any change to its pH on the addition of small quantities of either an acid or a base.
A buffer solution cannot be made with a strong acid because thy undergo complete dissociation. Therefore, any small addition of base or acid will result in very large changes in the pH of the solution. A buffer solution is made with a weak acid and its conjugate base or a weak base and its conjugate acid.
Why do Group 12 elements have different properties than Group 13
elements?
A. They have different numbers of neutrons.
B. They have different numbers of valence electrons,
C. They have different numbers of protons.
D. They have different atomic numbers.
The group 12 elements have different properties than group 13 elements because both have different number of valence electron.
What is valence electron?The electron present in valence shell is called valence electron.
The electronic configuration group 12 and group 13 is given below.
Electronic configuration Group 12 = (n-1)d10 ns2
Electronic configuration Group 13 = ns2np1
To learn more about Valence electron here.
https://brainly.com/question/13993867
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Assertion: When a strong acid is added to a buffer system consisting of a weak acid (HA) and its conjugate base (A-), the concentration of the conjugate base increases. Reason: A stoichiometric amount of the weak acid is converted to its conjugate base. Group of answer choices
Answer:
Both the assertion and reason are false
Explanation:
A buffer is a solution that resists changes in acidity and alkalinity. When a solution is buffered, it pH can only vary within a small range. A buffer is made up of a weak acid/base and its salt.
When a strong acid is added to a buffer solution, the conjugate base will react with the H+ from the strong acid to form the undissociated weak acid HA as follows; H+(aq) + A- (aq)→ HA(aq). Hence, H+ concentration decreases owing to its reaction with the A- thus the pH changes only slightly.
At the time when the strong acid should be added so here Both the assertion and reason are false
What is buffer?It is a solution that resists changes with respect to the acidity and alkalinity. When a solution should be buffered, it pH can only change within a small range. At the time when a strong acid should be added to a buffer solution, the conjugate base should be react with the H+ from the strong acid to form the undissociated weak acid.
Learn more about buffer here: https://brainly.com/question/13861408?referrer=searchResults
The Michaelis constant, Km, refers to the __________ at which a reaction proceeds at __________ of the maximum velocity. This constant most accurately reflects __________. The Michaelis constant, Km, refers to the __________ at which a reaction proceeds at __________ of the maximum velocity. This constant most accurately reflects __________. product concentration; one-half; structure of the substrate enzyme concentration; one-half; temperature optimum of the enzyme substrate concentration; one-half; the affinity of the substrate-enzyme interaction substrate concentration; one-fourth; pH optimum of the enzyme
Answer:
substrate concentration; one-half; the affinity of the substrate-enzyme interaction
Explanation:
The Michaelis constant, Km, refers to the substrate concentration at which a reaction proceeds at one-half of the maximum velocity. This constant most accurately reflects the affinity of the substrate-enzyme interaction.
30cm^3 of a dilute solution of Ca(OH)2 required 11 cm^3 of 0.06 mol/dm^. Hcl for complete neutralization. Calculate the concentration of the Ca(OH)^2 solution in mol/dm^3 and g/dm^3
Answer: Thus concentration of [tex]Ca(OH)_2[/tex] in [tex]mol/dm^3[/tex] is 0.011 and in [tex]g/dm^3[/tex] is 0.814
Explanation:
To calculate the concentration of [tex]Ca(OH)_2[/tex], we use the equation given by neutralization reaction:
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1,M_1\text{ and }V_1[/tex] are the n-factor, molarity and volume of acid which is [tex]HCl[/tex]
[tex]n_2,M_2\text{ and }V_2[/tex] are the n-factor, molarity and volume of base which is [tex]Ca(OH)_2[/tex]
We are given:
[tex]n_1=1\\M_1=0.06mol/dm^3\\V_1=11cm^3=0.011dm^3\\n_2=2\\M_2=?\\V_2=30cm^3=0.030dm^3[/tex] [tex]1cm^3=0.001dm^3[/tex]
Putting values in above equation, we get:
[tex]1\times 0.06mol/dm^3\times 0.011dm^3=2\times M_2\times 0.030dm^3\\\\M_2=0.011mol/dm^3[/tex]
The concentration in [tex]g/dm^3[/tex] is [tex]0.011mol/dm^3\times 74g/mol=0.814g/dm^3[/tex]
Thus concentration of [tex]Ca(OH)_2[/tex] is [tex]0.011mol/dm^3[/tex] and [tex]0.814g/dm^3[/tex]
Answer:
d
Explanation:
d
The volume of a sample of pure HCl gas was 221 mL at 20°C and 111 mmHg. It was completely dissolved in about 50 mL of water and titrated with an NaOH solution; 18.7 mL of the NaOH solution was required to neutralize the HCl. Calculate the molarity of the NaOH solution.
Answer:
[tex]molarity =6.9\times 10^{-3}\ M\\[/tex]
Explanation:
We know that , the reaction of HCl and NaOH is given as follows
[tex]NaOH+HCl=NaCl +H_2O[/tex]
Given that
Pressure = 111 mm Hg
[tex]P=111\times 13.6\times 10^{-3}\times 9.81\times 1000=14.809\ kPa[/tex]
Temperature = 20°C
T=20+273=293 K
Volume= 221 m L
V=0.221 L
Number of moles of HCl is given as follows
[tex]n=\dfrac{P\times V}{R\times T}\\n=\dfrac{0.148\times 0.221}{0.821\times 293}=1.3\times 10^{-4}\ moles[/tex]
From the above reaction we can say that
Number of moles of HCl=Number of moles of NaOH
Volume of NaoH is given as follows
V=18.7 = 0.0187 L
Therefore molarity
[tex]molarity =\dfrac{n}{V_{NaOH}}\\molarity =\dfrac{1.3\times 10^{-4}}{0.0187}=6.9\times 10^{-3}\ M\\molarity =6.9\times 10^{-3}\ M\\[/tex]
Calculate the pH of a solution obtained by mixing 477 mL of 0.17 M hydrochloric acid with 253 mL of M lithium hydroxide. Assume the combined volume is the sum of the two original volumes.
Answer:
pH = 0.984
Explanation:
Molarity LiOH = 2.1x10⁻²M
HCl will react with LiOH as follows:
HCl + LiOH → H₂O + LiCl
1 moles of HCl reacts per mole of LiOH
Moles of each reactant in solution are:
HCl = 0.477L ₓ (0.17mol / L) = 0.08109 moles HCl
LiOH = 0.253L ₓ (2.1x10⁻² mol / L) = 5.313x10⁻³ moles of LiOH.
That means LiOH is the limiting reactant and excess moles of HCl that will remain in solution are:
0.08109 mol - 0.005313mol = 0.0758 moles HCl
As HCl dissociates in water as H⁺ and Cl⁻ ions, you will have in solution 0.0758 moles of H⁺
pH = -log [H⁺] and [H⁺] = moles H⁺ / L of solution.
Volume of the mixture in liters is: 0.477L + 0.253L = 0.730L.
That means [H⁺] is 0.0758 moles of H⁺ / 0.730L = 0.1038M
Replacing:
pH = -log [H⁺]
pH = -log [0.1038]
pH = 0.984A 25.0 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution. The titration curve above was obtained with pH at equivalence point of around 8. The unknown compound is ________.
Answer:
Weak acid
Explanation:
A titration curve is a graphical description of the change in pH of the solution in the conical flask as the reagent is added from the burette. A titration curve can be plotted for the different kinds of acid and base titrations. The volume of the titrant is always plotted as the independent variable and the pH of the solution as the dependent variable. The equivalence point is read off from the titration curve. A titration curve is very important because it shows the pH at various points during the titration.
A weak acid/strong base titration leads to an equivalence point above 7. From the question, we were told that the pH at equivalence point lies around 8. Hence the unknown substance must be a weak acid.
Which property would cesium most likely have?
Answer: The property that cesium most likely would have is being ductile (able to be deformed without losing toughness) due it being a very soft, alkali metal which has a very low melting point of 83.3 °F or 28.5 °C
Answer:
The answer is B. Ductile.
Explanation: Cesium belongs to a category of metals. They are often silver, fairly soft, and very ductile. The answer is right on edge 2020.
Identify the type of reaction in the following and define each of them. (i) Carbohydrates are broken down to form glucose. (ii) Tarnishing of copper. (iii) Heating of ferric oxide with aluminium powder. (iv) Blue colour of copper sulphate solution disappears when zinc dust is added to it. (v) Dilute sulphuric acid is adeed to sodium hydroxide solution .
Answer:
(i) hydrolysis; (ii) combination; (iii) single replacement;
(iv) single replacement; (v) double replacement
Explanation:
(i) Carbohydrates are broken down to form glucose
Carbohydrates must react with water to form glucose.
For example,
C₆H₁₁O₅-O-C₆H₁₁O₆ + H-O-H ⟶ 2C₆H₁₂O₆
maltose glucose
This is a hydrolysis reaction — the reaction of a compound in which a molecule of water breaks one or more bonds to form new substances.
The reaction is not a decomposition (a reaction in which a compound breaks down into two or more simpler substances), because two different molecules are involved.
(ii) Tarnishing of copper.
Cu + S ⟶ CuS
This is a combination or synthesis reaction — in which two or more substances combine to form a single new substance.
(iii) Heating of ferric oxide with aluminium powder
Fe₂O₃ + 2Al ⟶ Al₂O₃ + 2Fe
This is a single displacement or single replacement reaction — in which one element replaces another element in a compound.
Here, Al is replacing Fe in its oxide.
(iv) Blue colour of copper sulphate solution disappears when zinc dust is added to it
CuSO₄ + Zn ⟶ ZnSO₄ + Cu
This is a single displacement or single replacement reaction.
Here, Zn is replacing Cu in its sulfate.
(v) Dilute sulfuric acid is added to sodium hydroxide solution
H₂SO₄ + 2NaOH ⟶ Na₂SO₄ + 2H₂O
2H⁺, SO₄²⁻ + 2Na⁺OH⁻ ⟶ 2Na⁺, SO₄²⁻ + 2H-OH
This is a double displacement or double replacement reaction — in which the positive and negative ions of two ionic compounds exchange places to form two new compounds.
The Na⁺ ions are replacing the H⁺ ions in the sulfuric, forming sodium sulfate and water,
Matter is composed of exceedingly small particles called atoms. An atom is the
smallest unit of an element that can participate in a -------
Answer:
Matter is composed of exceedingly small particles called atoms. An atom is the
smallest unit of an element that can participate in a chemical reaction.
Answer:
Chemical reaction.
Explanation:
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.
You're Welcome
~Kicho [nm68]
Period, group and atomic number of the elements that have the following electrical configurations: 1s2 2s2 2p3 1s2 2s2 2p6 3s2 1s2 2s2 2p5
Answer:
If you follow the periodic table and its orbitals, you'll see that the element that has the electron configuration of 1s²2s²2p³ is Nitrogen. It's period, group, and atomic number are 2, 15, and 7 respectively. The other 2 are Neon, who's period, group, and atomic number are 2, 18, and 10 and the last one is Fluorine, who's period, group, and atomic number are 2, 17, and 9.
What's the valency of sulphur for SO2?
Answer:
The valency of sulphur in SO2 is 4.
Hope this helps..
[tex]good \: luck[/tex]
what reaction type is solid sodium bicarbonate + acetic acid?
Answer:
the neutralization reaction occurs
25. Which answer best describes the continental rise? area of land that drops toward deep ocean basins 75 mile shallow flat area just off coastlines thick deposits of sediments carried off of the shelf the surf area along coastlines
Answer:
Thick deposits of sediments carried off of the shelf
Explanation:
The continental rise is a thick deposit of sediments that accumulate between the continental slope and the abyssal plain
A is wrong. The area of land that drops toward the deep ocean basins is the continental slope.
B is wrong. The 75-mile shallow flat area just off coastlines is the continental shelf.
D is wrong. The surf area along coastlines is the surf zone .
in terms of bonds, what would the molecule C3H6 be classified as
Explanation:
Cyclopropane is a cycloalkane conposed of three carbon atoms to form a ring. It has a rols as an inhalation anaesthetic. It is a cycloalkane and a member of cyclopropanes.
Answer:
Alkane
Explanation:
Adrian loves the pancakes! The problem is, the recipe serves only six, and he has 540 people in his family (including aunts, uncles, and cousins). Now, he needs help increasing the recipe to feed his entire family. However, Adrian is particular - he insists on using only three significant figures with scientific notation.
Answer:
ingredient. U.s unit. SI unit. SI unit(540)
flour. 2cups. ²/6. 180cups = 1.8×10²
milk. 2cups. ²/6. 180cups. =1.8×10²
eggs. 2. ²/6. 180eggs. =1.8×10²
melted butter. ⅓cup ¹/18. 30cups. =3×10¹
sugar. 1spoon. ¹/6. 90spoons. =9×10¹
baking powder 2spoons ²/6. 180spoons. =1.8×10²
salt. ½spoon. ¹/12. 45spoons. =4.5×10¹
Explanation:
1) to get the SI unit divide the U.S unit by 6
example:eggs = 2÷6. =²/6
2) to get the SI unit for 540 people ,multiply the SI unit by 540.
example:eggs ²/6×540. = 180
3)convert the answers to scientific notation
example:eggs =180. =1.8×10²
Help ya girl out plz
Answer:
The correct option is B
Explanation:
just did it edg 2020.
Answer:
the answer is c
Explanation:
in which sphere does a dolphin swim A. hydrosphere B. atmosphere C. magnetosphere D. lithosphere
Answer:
A. Hydrosphere
Explanation:
Hydro means water and dolphins swim in water.
I hope this helps :)
Which best describes a neutralization
reaction?
A) a reaction between an acid and a base
B) a reaction between two acids
C) a reaction between a base and a salt
D) a reaction between two salts
Explanation:
The Answer is a reaction between two acids
Which statement is true about oxygen-17 and oxygen-18? A Their atoms have identical masses B They do not have the same number of protons C They have different numbers of electrons D They are isotopes of oxygen
Answer:
option d
Explanation:
isotope means atoms with different mass no. 17 and 18 written on the left represent mass number
this is because atoms can differ in mass no.
option a is incorrect as they have different mass no,hence,different massoption b is incorrect as atoms-oxygen-17 and oxygen 18-of same element oxygen cannot differ in no of protonsif they had different no of electons they would have a charge like -1,-2,etcoption d is correct,because atoms can differ in mass no. isotope means atoms with different mass no. 17 and 18 written on the left represent mass number