96 POINTS
1. An atom of platinum has a mass number of 195 and an atomic number of 78. How many protons and neutrons are in this atom? – Calculate your answer and please note that work must be shown to earn credit.
neutrons=117
protons=78
Answer:
Platinum has mass number 195.
The atomic number of platinum =78
so the number of protons is 78.
By using simple formulas
we can find out that how many neutrons and protons are present in an atom of platinum-195.
Mass number = neutrons + protons
195=neutrons + 78
neutrons=195-78=117
so the number of neutrons is 117.
Which characteristic do valence electrons indicate about reactions between atoms? (1 point)
o electronegativity difference
o absolute electronegativity
o bond type
o bond number
The characteristic of reactions that depends on valence electrons is the bond type.
In chemistry, a chemical bond could be;
IonicCovalentThe type of bond formed depends on the number of valence electrons present. When there are few valence electrons on an atom, it mostly forms ionic bonds.
When there are more electrons on an atoms, it mostly forms covalent bonds and the electrons between the atoms are shared.
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Answer:
D: bond number
How many moles are in 29.5 grams of Ax?
A. 1.3 moles
B. 1.8 moles
C. 0.78 moles
D. 678 moles
The number of moles present in 29.5 grams of argon is 0.74 mole.
The atomic mass of argon is given as;
Ar = 39.95 g/mole
The number of moles present in 29.5 grams of argon is calculated as follows;
39.95 g ------------------------------- 1 mole
29.5 g ------------------------------ ?
[tex]= \frac{29.5}{39.95} \\\\= 0.74 \ mole[/tex]
Thus, the number of moles present in 29.5 grams of argon is 0.74 mole.
"Your question seems to be missing the correct symbol for the element"
Argon = Ar
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What will happen to the pH of sodium bicarbonate if vinegar is added to it?
Answer:
The overall chemical reaction between baking soda (sodium bicarbonate) and vinegar (weak acetic acid) is one mole of solid sodium bicarbonate reacts with one mole of liquid acetic acid to produce one mole each of carbon dioxide gas, liquid water, sodium ions, and acetate ions. The reaction proceeds in two steps
Which of the following observations indicates that atoms of all elements contain small, negatively charged particles?
Alpha particles are repelled by cathode rays of elements.
b.Cathode rays are deflected towards a positively charged rod.
c.A particular frequency of light is produced by a gas in an excited state.
d.Certain areas of the atom called orbitals contain all the charged particles
Answer:
cathode rays are deflected towards a positively charged rod
Explanation:
. Why does the element with the higher atomic number have a lower ionization energy than the element with the lower atomic number?
Answer:
first ionization energy is the amount of energy required to remove an electron from isolated gaseous atom
so when atomic no increase across aperiod the ionization energy become lower
it's my opinion am not sure ok
A total solar eclipse occurs because the moon can totally block the sun. If the moon was smaller or farther from earth, a total eclipse
Could occur
Could not occur
Answer:
both
Explanation:
id say that it could occur but also not as much. the moon would be smaller and further from the earth to where we would barely be able to see it. if the full moon is barely visible then im sure the total solar eclipse wouldn't be as noticeable as it is now. but thats just my opinion
The conversion of acetyl chloride to methyl acetate occurs via the following two-step mechanism: Reaction sequence of acetyl chloride to methyl acetateAccess the text alternative for PROBLEMS Kinetics and Rate Laws 6.49. Add curved arrows to show the movement of the electrons in each step. Write the rate equation for this reaction, assuming the first step is rate-determining. If the concentration of were increased 10 times, what would happen to the rate of the reaction? If the concentrations of both and were increased 10 times, what would happen to the rate of the reaction? Classify the conversion of acetyl chloride to methyl acetate as an addition, elimination, or substitution.
If the concentration of acetyl chloride is increased ten times the rate of reaction is increased ten times.
The conversion of acetyl chloride to methyl acetate is a substitution reaction. Recall that a substitution reaction is one in which a moiety in a molecule is replaced by another.
In this reaction, the CH3O- ion replaces the chloride ion. In the first step, the CH3O- ion attacks the substrate in a slow step. This creates a tetrahedral intermediate. Loss of the chloride ion yields the methyl acetate product.
The rate determining step is the formation of the tetrahedral intermediate. Since the reaction is first order in the acetyl chloride, if its concentration is increased ten times the rate of reaction is increased ten times.
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define the term chemotherapy.
I'm not able to understand that what is written in the pic.. As I can't understand this language..
Treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Chemotherapy may be given by mouth, injection, or infusion, or on the skin, depending on the type and stage of the cancer being treated.
Tính axit giảm dần của các chất C6H5 OH (1) ,p – CH3 OC6H4 OH (2), p-NO2C6H4OH (3) pCH3COC6H4OH (4), p-CH3C6H4 OH (5) là:
Answer:
di ko po Alam sorry
Explanation:
sorry sorry sorry sorry sorry
What sign of chemical change occurs during chemiluminesence?
Production of heat
Production of a gas
Production of light
O Production of a solid (precipitation)
Answer:
Emission of Light
Explanation:
Chemiluminescence is the emission of light as the result of a chemical reaction, and not a property of a specific compound.
Dont know if you were asking for this but hope it helps
Consider the reaction.
2Pb(s)+O2(g)⟶2PbO(s)
An excess of oxygen reacts with 451.4 g of lead, forming 386.5 g of lead(II) oxide. Calculate the percent yield of the reaction.
Answer:837.9
Explanation:add those 2 numbers
how many atoms of vanadium are in 1.28 grams of vanadium
The number of atoms in 1.28 grams of vanadium is 1.51×10²² atoms
Avogadro's hypothesisFrom Avogadro's hypothesis,
1 mole of Vanadium = 6.02×10²³ atoms
But
1 mole of Vanadium = 51 g
Thus,
51 g of Vanadium = 6.02×10²³ atoms
How to determine the atoms in 1.28 g of Vanadium51 g of Vanadium = 6.02×10²³ atoms
Therefore,
1.28 g of Vanadium = (1.28 × 6.02×10²³) / 51
1.28 g of Vanadium = 1.51×10²² atoms
Thus, 1.51×10²² atoms is present in 1.28 g of Vanadium
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A student creates a sports drink by dissolving 5.0 g of powder in 250 mL of water. The green colour of the drink is due to the presence Green Dye X, which has a lambdamax of 630 nm. A calibration curve (absorbance versus concentration) at lambdamax is created for varying concentrations (mM) of Green Dye X which has the equation y = 26.4x. If 1.0 mL of the sports drink is diluted to 10. mL with water, then the absorbance is measured to be 0.450, what is the mass percent of Green Dye X in the drink powder if the molecular weight is 418.4 g mol-1?
The mass percent of Green Dye X in the drink powder if the molecular weight is 418.4 g/mol is 0.355%
Beer's law explains the relation between the concentration of a solution to its absorbance (A) by using the equation.
A = ∈×C×Lhere:
∈ = molar absorptivityL = path lengthNow from the calibration curve in the question, the plot between the absorbance and the concentration gives a straight line of y = mx.
Here
y = absorbance x = concentrationThe equation of the calibration curve is given as:
y = 26.4xi.e.
0.450 = 26.4x[tex]\mathbf{x = \dfrac{0.450}{26.4}}[/tex]x = 0.017 mMIf the sports drink was 10 times diluted while taking the absorption measurement. Then, the actual concentration of green dye in the sports drink is:
= 0.017 mM × 10
= 0.17 mM
The number of moles of green dye in 250 mL (i.e. 0.25 L) sports drink is estimated as:
= 0.17 mmol/L × 0.25 L
= 0.0425 mmol
However, the mass of the green dye present in the sports drink is
= 0.0425 mmol ×418.4 g/mol
= 17.782 mg
Finally, the mass percent of green dye in the drink powder is:
[tex]\mathbf{ = \dfrac{mass (dye)}{mass (powder)} \times 100\%}[/tex]
[tex]\mathbf{ = \dfrac{17.782 \ mg }{5.0 \ g} \times 100\%}[/tex]
[tex]\mathbf{ = \dfrac{17.782 \ mg }{5000 \ mg} \times 100\%}[/tex]
= 0.355 %
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What is condensation
Carbon has three isotopes: carbon-12, carbon 13, and carbon-14. If the average atomic mass on the
periodic table for carbon is 12.011 amu, which isotope is most abundant? Explain your answer using a complete sentence.
Answer
The most abundant carbon isotope is carbon-12
Explanation:
The relative atomic mass of carbon is 12.011, which is extremely close to 12.0. This means that the masses C-13, and C-14 are practically negligible when contributing to the relative atomic mass of carbon.
In fact, the C-12 isotope makes up 98.9% of carbon atoms, C-13 makes up 1.1% of carbon atoms, and C-14 makes up just a trace of carbon atoms as they are found in nature.
1. What is the shape of an organic molecule containing a triple bond with respect to the carbons on either side of the bond?
Explain your answer
Answer:
The alkyne is linear
Explanation:
Any molecule with a triple bond is considered an alkyne. In regards to the shape, because carbon can only bond to 4 different atoms at once a triple bond fills in 3 of the required 4 atoms needed to reach the molecules ground state (when it's most stable). The more electrons shared between atoms, the shorter the bond will be which results in a stronger and more linear line. Keep in mind a quadruple bond is not possible between carbons as of now.
which of the two glasses the ingredients dissolved completely class/sand or sugar
Answer:
sugar
Explanation:
sand will not dissolve in water because the bond in water isn't strong enough to dissolve it.
so sand is a big no.
so the answer is the other option: which is sugar.
Describe how you could show by adding aqueous sodium hydroxide and aqueous ammonia that a solution contained zinc ions.
Answer:
Learning Task 3. Solving word problems involving multiplication of deci-
the
A cstep in solving word problems. Do these in your notebook. ),
1. A clerk is paid P 45.25 per hour for 40 hours a week, 1.50 times the
regular rate for overtime and double the rate for a holiday. How much
holiday?
2. fofkmputer programmer earns a regular hourly rate of P50.00. If he
worked 42.75 hours in a week, how much did he earn?
3. Arthur earns P1350.00 a day. He sets aside 0.10 of this for savings.
How much does he save in a month?
4. Mr. Fernandez has a monthly pay of P 5,450. The tax deducted from
year?
5. Dianne works 2.5 hours a day from Monday to Friday and 3.75 hours
his a
on Saturday. If he is paid P25.00 per hour, how much does he earn in
a
week?
Explanation:
Learning Task 3. Solving word problems involving multiplication of deci-
the
A cstep in solving word problems. Do these in your notebook. ),
1. A clerk is paid P 45.25 per hour for 40 hours a week, 1.50 times the
regular rate for overtime and double the rate for a holiday. How much
holiday?
2. fofkmputer programmer earns a regular hourly rate of P50.00. If he
worked 42.75 hours in a week, how much did he earn?
3. Arthur earns P1350.00 a day. He sets aside 0.10 of this for savings.
How much does he save in a month?
4. Mr. Fernandez has a monthly pay of P 5,450. The tax deducted from
year?
5. Dianne works 2.5 hours a day from Monday to Friday and 3.75 hours
his a
on Saturday. If he is paid P25.00 per hour, how much does he earn in
a
week?
helpppppppppppppppppppppp
Answer:
The process in which plants release water through their leaves back into the air
Explanation
Answer:
The process in which plants release water through their leaves back into the air.
Hope this helps!
The Lewis electron-dot structure of oxygen has how many dots?
Answer:
Oxygen has 6 valence electrons and follows the octet rule.
If you were drawing a lewis structure for O2, there would be a total of 12 valence electrons (6 x 2 = 12).
The completed structure would have a double bond between the two oxygen atoms with 2 lone pairs per oxygen, giving you a total of 8 electrons that are lone pairs (or dots).
Calculate the pOH of an aqueous solution of .0.073 M LiOH
Considering the definition of pOH and strong base, the pOH of the aqueous solution is 1.14
The pOH (or potential OH) is a measure of the basicity or alkalinity of a solution and indicates the concentration of ion hydroxide (OH-).
pOH is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
On the other hand, a strong base is that base that in an aqueous solution completely dissociates between the cation and OH-.
LiOH is a strong base, so the concentration of the hydroxide will be equal to the concentration of OH-. This is:
[LiOH]= [OH-]= 0.073 M
Replacing in the definition of pOH:
pOH= -log (0.073 M)
pOH= 1.14
In summary, the pOH of the aqueous solution is 1.14
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brainly.com/question/16032912?referrer=searchResults brainly.com/question/13557815?referrer=searchResultsYou and your family have just arrived in Water Cycle Land. You are going on a new ride called the Water Cycle. You sit in your seat and the ride begins. All of a sudden something goes wrong. Your body is turning into a water droplet! Think about what you have learned about the water cycle. Now tell a story about what happens to you as you travel through the water cycle. By the way, how do you get your body back to normal?
Answer: you dont drink water for years
Explanation: dont drink water for years on end
Electronegativity is a chemical property which describes how well an atom can attract an electron to itself. Values for electronegativity run from 0 to 4. The difference in electronegativity (ΔEN) is used to predict whether a bond between atoms will be ionic or covalent. It can also be used to predict if the resulting molecule will be polar or nonpolar.
If a bond was made between the two atoms shown below, would the bond be (1) covalent, i.e. ΔEN = ≤ 0.4, (2) polar covalent i.e. ΔEN > 0.4 and ≤2.0, or (3) ionic, i.e. ΔEN > 2.0? Enter 1 for covalent, 2 for polar covalent, 3 for ionic.
protactinium, francium
#protactinium
It lies in 7th period having Z=91The outer electronic configuration is 6d^17s^2
d-block element(transition)So it will form polar covalent bond (2)
#Francium
Z=87Outer electronic configuration 7s^1
s-block elementIt will form ionic bond (3)
What are acids ? Will they harm skin
Hydrochloric acid can cause damage if it comes into contact with your lungs, eyes, stomach, or skin. If hydrochloric acid comes into contact with your skin, it can cause: chemical burns. scarring.
Determine the molar solubility for Cr(OH)3 Ksp = 6.3x10^-31 ....
a) Set up the ICE table Cr(OH)3 (s) <-> Cr^3+ (aq) + 3OH^- (aq)
b) Ksp expression
c) Determine molar solubility
The equilibrium constant shows the extent of dissolution of a substance in solution. The molar solubility of the compound here is 1.2 * 10^-8 M.
What is solubility product?The solubility product is the equilibrium constant that shows the extent to which a substnace is dissolved in soution.
Now let us set up the ICE table as shown;
Cr(OH)3 (s) <-> Cr^3+ (aq) + 3OH^- (aq)
I 0 0
C +x +3x
E x 3x
Ksp = [Cr^3+] [OH^- ]^3
6.3x10^-31 = [x] [3x]^3
6.3x10^-31 = 27x^4
x = 4√6.3x10^-31 /27
x = 1.2 * 10^-8 M
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How many molecules of carbon dioxide and how many molecules of water would be produced from 4 molecules of methane (CH4) reacting with 8 molecules of oxygen (O2)
Answer:
4
Explanation:
water would be produced from 4 molecules of methane (CH4) reacting with 8 molecules of oxygen (O2)
The products of the combustion of hydrocarbon are 4 molecules of carbon dioxide and 8 molecules of water.
What is the combustion reaction?A combustion reaction can be described as a reaction that produces fire and takes place at a high temperature. It is an exothermic reaction as well as a redox reaction that usually takes place between a fuel and mostly oxygen gas.
Examples of Combustion Reactions such as during the combustion of 4 molecules of methane reacting with 8 molecules of oxygen gas to give carbon dioxide and two molecules of water.
[tex]4CH_4 + 8O_2\longrightarrow 8H_2O + 4CO_2[/tex]
Oxygen is the essential reactant for combustion because the combustion is not possible in the absence of oxygen. Complete combustion takes place when a fuel burns completely to produce heat with oxygen and carbon dioxide.
The burning of wood fuels in the presence of air is an example of combustion. The carbon present in wood reacts with oxygen gas in the air to liberate heat and form gaseous products.
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#SPJ2
Explain why the element of an atom doesn't change if you remove or add electrons or neutrons
Answer: Does not change.
Explanation:
The atomic number and the electrical charge of that atom would remain unchanged. Neutrons do not carry an electrical charge so adding or removing them from the nucleus does not change the electrical charge of the nucleus.
1. Oxygen was discovered by Joseph Priestley in 1774 when he heated mercury (II) oxide, HgO, to decompose it to form its constituent elements. How many moles of mercury (II) oxide are needed to produce 125 g of oxygen?
Given:
Unknown:
Mole ratio:
Solution:
2. In a blast furnace, iron (III) oxide is used to produce iron by the following (unbalanced) reaction:
Fe2O3(s) + CO(g) Fe(s) + CO2(g)
If 4000 g of Fe2O3 is available to react, how many moles of CO are needed?
Given:
Unknown:
Mole ratio:
Solution:
Final answer:
ugh pls help:(
Answer:
1. 7.81 moles HgO
2. n = mass/molar mass = (4000 g)/(159.69 g/mol) = 25.05 mol.
Explanation:
How many moles of mercury (II) oxide are needed to produce 125 g of oxygen?
2HgO ==> 2Hg + O2
125 g O2 x 1 mol O2/32 g x 2 mol HgO / mol O2 = 7.81 moles HgO
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If 4000 g of Fe2O3 is available to react, how many moles of CO are needed?
The no. of moles of CO are needed = 75.15 mol.
Fe₂O₃ + 3CO → 2Fe + 3CO₂,
It is clear that 1 mol of Fe₂O₃ reacts with 3 mol of CO to produce 2 mol of Fe and 3 mol of CO₂.
If 4.00 kg Fe₂O₃ are available to react, how many moles of CO are needed?
We need to calculate the no. of moles of 4.00 kg Fe₂O₃:
n = mass/molar mass = (4000 g)/(159.69 g/mol) = 25.05 mol.
Using cross multiplication:
1 mol of Fe₂O₃ need → 3 mol of CO to react completely, from stichiometry.
25.05 mol of Fe₂O₃ need → ??? mol of CO to react completely.
The no. of moles of CO are needed = (3 mol)(25.05 mol)/(1 mol) = 75.15 mol.
In which species does sulphur have the more negative oxidation number? Answers: A. H2S B. S8 (elemental form of sulphur) C. H2SO3 D. K2SO4
Answer:
H2S
Explanation:
the oxidation number of S is -2.