Sodium has a mass number of 23amu. Since sodium has 11 protons, the number of neutrons must be 23 – 11 = 12 neutrons.
A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over the next few minutes? Molecules in both the metal and the surrounding air will start moving at lower speeds. Molecules in both the metal and the surrounding air will start moving at higher speeds. The air molecules that are surrounding the metal will slow down, and the molecules in the metal will speed up. The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down. Mark this and return
What are the basic elements of selection of proffesion?describe any two
Answer:
overall I think one answer
El fluoruro de hidrógeno HF que se utiliza en
la obtención de los freones (los cuales
destruyen la capa de ozono de la
estratosfera), se prepara mediante la
siguiente reacción: CaF2 + H2SO4
CaSO4 + 2HF Si se hacen reaccionar 50gr
de CaF2 con 100 gr de H2SO4 (masas
atómicas Ca=40,F=19, H=1, S=32, O=16)
Answer:
25.6g de HF son producidos
Explanation:
...¿Cuánto HF es producido?
Para resolver este problema debemos convertir la masa de cada reactivo a moles usando su masa molar. Como la reacción es 1:1, el reactivo con menor número de moles es el reactivo limitante. Con las moles del reactivo limitante podemos obtener las moles de HF y su masa así:
Moles CaF2:
Masa molar:
1Ca = 40g/mol
2F = 19*2 = 38g/mol
40+38 = 78g/mol
50g CaF2 * (1mol/78g) = 0.641 moles CaF2
Moles H2SO4:
Masa molar:
2H = 2g/mol
1S = 32g/mol
4O = 64g/mol
98g/mol
100g H2SO4 * (1mol / 98g) = 1.02 moles H2SO4
Como las moles de CaF2 < Moles H2SO4: CaF2 es reactivo limitante.
Moles HF usando la reacción:
0.641 moles CaF2 * (2mol HF / 1mol CaF2) = 1.282 moles HF
Masa HF:
Masa molar:
1g/mol + 19g/mol = 20g/mol
1.282 moles HF * (20g/mol) =
25.6g de HF son producidosWhat type of a liquid will have a pH value equal to 7? (1 point)
1. Which of the following species exhibit tetrahedral geometry?
a. CCl4 b. PCI5 c. NH3 d. CO2
2. Which statement correctly describes the Valence Shell Electron Pair Repulsion (VSEPR) Theory? The valence electron pairs are__________.
a. The valence electron pairs are given by the group number in the periodic table.
b. The valence electron pairs are the outermost electrons of the atom that areinvolved in the bonding.
c. The valence electron pairs repel one another and tend to stay as far apart aspossible.
d. The valence electron pairs are the lone pairs of the atom.
3. Which of the following statements about resonance is TRUE?
I. Resonance hybrids occur because a compound changes back and forth between two or more resonancestructures
II. Resonance structures differ in the arrangement of electrons but not in the arrangement of atoms.
III. Resonance hybrids contain delocalized electrons.
IV. Resonance structures for a given compound always contribute equally to the resonance hybrid.
V. Resonance structures occur when there are two or more valid Lewis structures for a given compound.
VI. Resonance hybrids are a composite of resonance structures.
a.I, II, V, VI
b. II, III, IV, VI
c. II, III, V, VI
d. II, IV, V, VI
4. How many resonance forms will nitrate ion (NO3) have?
a. - 1 b. 1 c. 2 d. 3
5. What is the first noble gas?
a. Xenon b. Radon c. Helium d. Krypton
6. What is the principle used for filling of atomic orbitals?
a. Azimithual Principle
b. Hund's Principle
c. Pauling's Exclusion Principle
d. Aufbau Principle
7. How many electrons can "m" shell accommodate?
a. 16 b. 17 c. 18 d. 19
8. What number of shells used for the accommodation of electrons in an atom? a. one b. two c. three d. four
9. What distribution does the electron configuration describe?
a. protons
b. neutrons
c. electrons
d. ions
10. How many total electrons can the "p" orbitals hold?
a. 3 b. 1 c. 7 d. 6
11. Who are the founding fathers of Quantum Mechanics?
a. Werner Karl Heisenberg
b. Isaac Newton
c. Erwin Schrodinger
d. a and c
12. There are _types of quantum numbers.
a. 2 b. 4 c. 5 d. 7
13. Which of the following elements can only form one bond in a Lewis structure? a. H b. O c. Al d. N
14. Which rule states that electron will go into empty orbitals of the same energy before entering into an orbital with an electron present?
a. Hand's rule
b. Hund's rule
c. Pauli Exclusion Principle
d. Aufbau Principle
15. What is the definition of diamagnetic atom?
a. An atom where all of the electrons are paired
b. An atom where some of the electrons are paired.
c. An atom where none of the electrons are paired.
d. An atom attracted to a magnetic field.
Answer:
a
Explanation:
Its because ammonium has thee hydrogen atoms
How many moles of carbon are in the sample?
Answer:
12.01 grams per mole
Explanation:
theres no sample or example so if theres grams of Carbon, convert it to moles using 12.01g/mol
The nonmetals include which of the following groups? Use the periodic table to answer the question. Check all that apply.
halogens
alkali metals
lanthanides
noble gases
alkaline earth metals
Answer:
En el grupo de los no metales se incluyen los halógenos (flúor, cloro, bromo, yodo, astato y téneso), que tienen 7 electrones en su última capa de valencia y los gases nobles (helio, neón, argón, kriptón, xenón, radón), que tienen 8 electrones en su última capa (excepto el helio, que tiene 2).
Explanation:
halógenos
Answer:
1,4
Explanation:
1. A) Calculate DO of water at 25 0 C, P 0 = 1.01x10 5 Pa; given: water vapor pressure (25 0 C) is 3.2x10 3 Pa and Henry constant of oxygen in water is 1.3x10 -8 mol/l.Pa b) How's DO content changed as increase or decrease water temperature? Explain.
Answer:
cfvgbhnjmk,
Explanation:
what is the [h+] if the ph of a solution is 11.13
pls help
Explanation:
[tex][{H}^{ + }] = {10}^{ - pH} [/tex]
[tex] = {10}^{ - 11.13} [/tex]
[tex] = {10}^{ (- 11 - 0.13)} [/tex]
[tex] = {10}^{ - 0.13} \times {10}^{ - 11} [/tex]
[tex] = 0.741 \times {10}^{ - 11} \frac{mol}{litre} [/tex]
HOPE IT HELPS YOUIn an electrically neutral atom, the number of
protons equals the number of neutrons.
protons equals the number of electrons.
neutrons equals the number of electrons.
A. Protons equals the number of neutrons
B. Protons equal the number of electrons
C. Neutrons equals the number of electrons
Answer: B
Answer:
B
Explanation:
because protons have a +1 charge and electrons have a -1 charge, so if an atom is neutral it must have the same amount of protons and neutrons
một oxit của photpho có thành phần trăm của P bằng 43,66% . Biết phân tử khối của Axit bằng 142đvC. Công thức hóa học của Axit là ?
Answer:
câu trả lời trong hình ảnh
how does liquid carbon dioxide connect to organic chemistry
please I need long answers
Match the reaction to the type that best describes it.
2HCl → H2 + Cl2
?
Combination
NaF + KBr →
NaBr + KE
?
Decomposition
Mg + MnCl2 →
-Mn + MgCl2
?
Single replacement
2Na + 02 →
Na2O2
?
Double replacement
Answer:
2HCl → H2 + Cl2 = decomposition
NaF + KBr → NaBr + KF = double replacement
Mg + MnCl2 → Mn + MgCl2 = single replacement
2Na + 02 → Na2O2 = combination
Explanation:
A chemical reaction involves the conversion of one or more substances called REACTANTS into other substances called PRODUCTS. There are different types of reactions depending on how it occurs, they include:
- Combination or synthesis reaction is a type of reaction in which two or more elements combine to form a single product. Example is:
2Na + 02 → Na2O2
- Single replacement is a type of reaction where one element is replaced by another in a compound or molecule. Example below shows that Manganese (Mn) is replaced by magnesium (Mg):
Mg + MnCl2 → Mn + MgCl2
- Double replacement is a type of reaction where two elements are replaced by other elements at a time. Example is:
NaF + KBr → NaBr + KF
- Decomposition is a type of reaction in which one molecule or compound is broken down into two or more products. Example is:
2HCl → H2 + Cl2
¿Cuántos ml de alcohol contiene una lata de cerveza de 375 ml si tiene una concentración 4% v/v?
Answer:
15 mL
Explanation:
El valor de concentración de 4% v/v nos dice que de cada 100 mL de cerveza, 4 mL son de alcohol.
Con eso en mente podemos calcular los mL de alcohol presentes en 375 mL, de la siguiente forma:
375 mL * 4/100 = 15 mLEn 375 mL de cerveza de concentración 4% v/v, hay 15 mL de alcohol.
How many molecular of H2O and O2 are present in 8.5g of H2O2 ?
2H2O+O2--->2H2O2
8.5 gm H2O2=0.25 mole
hence H2O is also 0.25 mole i.e.4.5 gm
O2is 0.125 mole i.e.4 gm
I’ll mark you as brainlister
2002040_MIJ COMP SCI 1_SEM 1 CR_PY
The three main types of scientific investigations are descriptive, comparative, and experimental. Which components
are included in all three types of investigations?
a scientific question
an independent variable
a dependent variable
a procedure
a control group
a conclusion
Answer:
a scientific question
Procedure
Conclusion.
Explanation:
Scientific investigation is usually carried out to explain and give answers to natural phenomenon. Now, this scientific investigation is performed through the three main types as described in the question.
With that being said, the most common parts of all types of investigation are :
1. Scientific question: In this stage, questions are usually asked on the basis of observation made which could be answered.
2. Procedure: In this stage, the dimension of the steps are followed to answer and test the scientific question.
3. Conclusion: This is the primary aim that we check when done with our sample values
The most common carrier of communicable diseases are
a.cockroach
b.housefly
c.mosquito
d.spider
housefly
Explanation:
Because it one of the affective vector of disease carrier and it always roam towards wastes and dirty materials likely to get attracted . And it carries contagious disease from hospitals , infected patients , etc .
A gamma wave has______
energy than a radio wave.
Answer:
A gamma wave has higher energy than a radio wave.
What pollutants can contribute to acid precipitation and how are these pollutants generated?
Answer:
I don't know I don't know about question but I can try to find it
Explanation:
I don't know about question but I can try to find it
The general shape that an electron is located within an energy level_____
Answer:
valence
Explanation:
the level of energy electrons have within a general shape the energy level is valence.
1.25 X 10^24 molecules of chlorine gas react with sodium to form how many grams of sodium
chloride?
2Na + Cl2
--> 2NaCl
Answer:
241.28 g NaCl(s)
Explanation:
Given 1.25 x 10²⁴ molecules of Cl₂ = 1.25 x 10²⁴molecules Cl₂(g)/6.023 x 10²³ molecules/mole = 2.08 mole Cl₂(g)
2Na(s) + Cl₂(g) => 2NaCl(s)
excess 2.08mole ? mole
∴moles NaCl(s) formed from 2.08 moles Cl₂(g) = 2(2.08 mole NaCl(s))
= 4.16 mole NaCl(g) = 4.16 mole NaCl(s) x 58 g NaCl(s)/mole NaCl(s) = 241.28 g NaCl(s)
Crystals of sodium chloride were prepared by the following method.
1 25.0 cm3
of dilute hydrochloric acid was accurately measured into a conical flask.
2 Aqueous sodium hydroxide was added until the solution was neutral. The volume of
sodium hydroxide added was measured.
3 The solution was evaporated and the crystals washed with approximately 15 cm3
of water.
Which row shows the pieces of apparatus used to measure the 25.0 cm3
of hydrochloric acid, the
volume of aqueous sodium hydroxide and the 15 cm3
of water?
Answer: the answer is C
IF U MIGHT NEED AN EXPLANATION FEEL FREE TO COMMENT
The laboratory equipment like the burette, pipette, and measuring cylinders are used in process of titration process. The solution of NaOH is added by the burette. Thus, option C is correct.
What is titration?Titration has been the analytical technique that uses the known and measured quantity of the solution to estimate the volume of another solution with an unknown volume and known molar concentration.
The laboratory equipment like burette, pipette, and measuring cylinders are used in measuring the volume in the titration process. The burette is filled with sodium hydroxide to measure its quantity.
The pipette is used to transfer the volume of the solution that is known (hydrochloric acid) and the measuring cylinder is used to measure the liquid (water) that is used in chemistry experiments.
Therefore, option C. pipette, burette, and measuring cylinder are the apparatus used in the titration process.
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A 15.8 g sample contains 3.60 g F, 4.90 g H, and 7.30 g C. What is the percent composition of hydrogen in this sample?
Answer: 22.7848% F or 23%
Explanation: %F = 3.6g/15.8g • 100% = 22.7848% F
The percentage composition of hydrogen in the given sample is equal to 31%.
What is percentage composition?The percentage composition of a given compound can be described as the ratio of the quantity of each element to the total quantity of individual elements in the compound multiplied by 100. The quantity can be measured in terms of grams of the elements present in the sample.
The percent composition is expressed in its composition in terms of all the elements present. Thus, it helps in the chemical analysis of any given compound.
The percentage composition is expressed using the following formula,
Percentage composition of E = (E/T) × 100
Where E represents the total quantity of element E present in the compound and T represents the total quantity of all the elements present in the compound.
Given, the mass of the F, H, and C is 3.60g, 4,90 g, and 7.30 g respectively.
The total mass of the given sample = 15.8 g
The mass of the hydrogen in the sample = 4.90 g
The percent composition of H = (4.90/15.8) × 100 = 31 %
Therefore, the percent composition of hydrogen in this sample is 31%.
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describe the formation of covalent bond in methane (5 marks)
Answer: Covalent bonding is when atoms of different elements share electrons
Explanation: Taking Methane CH₄
it contains Hydrogen and Carbon atoms pairing electrons. the electronic configuration for carbon is 2,4 that is to say it has 4 electrons in its valence shell (outer shell) and hydrogen has 1 so carbon shares its four electrons with four hydrogen atoms thus forming a covalent bond. so they now have a stable arrangement of electrons in their outer shell ,thus giving CH₄There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, sharing of electron is the only basis for the formation of covalent bond in methane.
What is chemical Compound?Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
Carbon has an electrical configuration of 2,4. Hydrogen only has one electron in its valence shell, whereas carbon contains four electrons. In order to create methane, carbon forms a covalent connection with four hydrogen atoms, sharing its four electrons with them.
Therefore, sharing of electron is the only basis for the formation of covalent bond in methane.
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3. If there were multiple products comment on finding the mixture melting point of the products. Does your sample appear to be a mixture or pure
Answer:
If there were multiple products, we can take each product and mixed with a sample of a pure compound that we suspect might be the same as the product. Then, we taking the melting point of this mixture that contains one of our product and pure sample. Then, we can observe the change in melting point, if there is no change in melting point or the melting stays in the same range of the pure compound. Then, the that product along with the pure sample are actually the same compound, not a mixture of two compounds. However, if the melting point for our pure sample compound changed or didn't stay in the same range after the mixing with on of our products. then we can conclude that this product and the pure sample are completely different compound, and indeed they are a mixture.
Someone please do a True or false of all of these
Answer:
1. False
2. True
3. False
4. False
5. True
6. False
7. True
8. True
9. True
different oil refineries in UAE
Answer:
Petroleum refinery capacity in the UAE 2009-2018
In 2018, the total production capacities of all refineries in the UAE were 1.13 metric barrels per day. Total total production capacity of the al-Ruwais refinery in the United Arab Emirates was approximately 817,000 metric barrels per day.
It is known that oxygen contains 1 percent of the air. If 50 liters of wind, how much oxygen is needed? *
Answer:
25 PRECENT
Explanation:
Both aldehydes and ketones contain a carbonyl group a functional group with a carbon oxygen double bond, hence the carbonyl in aldehydes and ketones forms sp²hybridization.
Answer:
Both aldehydes and ketones contain a carbonyl group a functional group with a carbon oxygen double bond, hence the carbonyl in aldehydes and ketones forms sp²hybridization.
Explanation:
The structure of carbonyl group is -C=O-
The hybridization of carbon can be identified by couting the number of surrounding atoms.
In carbonyl compounds, carbon is directly bonded with three atoms.
One is oxygen, and the other two are other carbons.
With oxygen carbon has a double bond.
Hence, this three corresponds to sp2 hybridization.
Thus, the given statement is correct.
