Answer:
a. 1 cm^3 = 1 mL
explanation:
Metals like potassium and sodium are kept in paroffin oil. Why?
Answer:
because they are high reactive to the air thats why we keep them in paroffin oil
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 .
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
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)
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 producidosA 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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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
In 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
What are the basic elements of selection of proffesion?describe any two
Answer:
overall I think one answer
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
he ______ is the depth in the ocean at which calcareous skeletal material first begins to dissolve. Multiple choice question.
Answer: lysocline
Explanation:
Lysocline is the depth in the ocean at which calcareous skeletal material first begins to dissolve. It is the depth of the ocean whereby the dissolution rate of calcite has a dramatic rise.
Lysocline is also referred to as the transition zone upper bound where the CaCO3 content drops.
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
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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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:
Select the correct answer.
0.22 M
HCI
Unknown
LiOH
What is the concentration of the base (LIOH) in this titration?
1.0 ml
0.5 ml
Initial
burette
reading
Final
burette
reading
13.3 ml
18.5 ml
OA
0.16 M
ОВ.
0.15 M
OC. 0.22 M
OD
18 M
O E
0.5 M
Daset
Answer:
=0.15M
Explanation:
To get the moles of the unknown LiOH, calculate the number of moles of HCl in 12.3mL.
Using the stoichiometric coefficient, mole ratio 1:1.
This means that the number of moles is the same. This number of moles is contained in 18mL. Then Calculate the molarity (concentration) which is in 1000mL
See the explanation from the image I have shared with you for calculations.
explain with example the need of standard measurement system
Answer:
A standard system of measurement is very important because it helps us from making mistakes at the moment of doing calculations and correctly working...
Answer:
A standard measurement system is important because it allows scientists to compare data and communicate with each other about their results. Metric System – is a measurement system based on the number 10.
How many moles of water vapor are formed. when 10 litres of butane gas c4h10 is burned in oxygen at STP
Using the idea of the molar volume of butane gas, we have 2.23 moles of water vapor.
What is a reaction equation?The term reaction equation shows the conversion of reactants to products. First of all, we must get down the reaction equation as follows;
C4H10(g) + 13/2O2(g) ----> 4CO2 (g) + 5H2O(g)
From the balanced reaction equation;
1 mole of butane gas yields 5 moles of water vapor. Since 1 mole of butane gas occupies 22.4 L. Hence;
22.4 L of butane yields 5 moles of water vapor
10 L of butane gas yields 10 L * 5 moles/22.4 L = 2.23 moles
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Lead is a toxic metal that affects the central nervous system. A Pb-contaminated water sample contains 0.0012 % Pb by mass. What volume of the water in milliliters contains 100 mg of Pb
Answer:
8.3 × 10³ mL
Explanation:
Step 1: Calculate the mass of water that contains 100 mg of Pb
The concentration of Pb in the sample is 0.0012% by mass, that is, there are 0.0012 g of Pb every 100 g of water. The mass of water that contains 100 mg (0.100 g) of Pb is:
0.100 g Pb × 100 g Water/0.0012 g Pb = 8.3 × 10³ g Water
Step 2: Calculate the volume corresponding to 8.3 × 10³ g of water
Since the solution is diluted, we will assume the density of the sample is equal than the density of water (1 g/mL).
8.3 × 10³ g × 1 mL/1 g = 8.3 × 10³ mL
The volume of the water in milliliters contains 100 mg of Pb is;
V = 8.3 × 10³ mL
Volume of SolutionWe are given the concentration of Pb in the sample as 0.0012% by mass.
That means that there are 0.0012 g of Pb in every 100 g of water.
Thus, the mass of water that contains 100 mg (0.100 g) of Pb is calculated as;
(0.100 g Pb × 100 g of Water)/0.0012 g of Pb = 8.3 × 10³ g of Water
Now, we know that the density of water (1 g/mL) but we are not given the density of the sample.
Thus, since the solution is diluted we can equally say that;
Density of sample = 1 g/mL
Formula for Volume is;
V = mass/density
Thus;
V = 8.3 × 10³ g/1 g/mL
V = 8.3 × 10³ mL
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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:
What type of a liquid will have a pH value equal to 7? (1 point)
I’ll mark you as brainlister
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
describe the formation of ionic bonds in potassium chloride compound (5 marks)
Answer:
When the two atoms are in contact, potassium readily transfers its outer electron to chlorine which readily accepts it, resulting in both atoms achieving a state of eight outermost electrons. With this electron transfer, the ionic bond in KCl is formed.
how does liquid carbon dioxide connect to organic chemistry
please I need long answers
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.
please help. need this asap!!
Answer:
E.....Na2I.,.
Explanation:
Cuz sodium has a Vallency..1......lodide has Vallency 2
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.
PLEASE HELP ASAP!!!!!!!!
Answer:
ouch......it's kinda a practical question..
Answer: ?
Explanation: what was the answer?
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.
Which statement is the best description of a chemical bond
Answer:
What are your given options? I can't answer unless I know those :)
Explanation:
