Answer:
consistent
Explanation:
in this phrase, consistent means that your results do not falter and prove that your answer is performed correctly and efficiently. if an experiments results are repeated and you get a different outcome, you should restart your process and evaluate what mightve hone wrong.
Calculate the number of atoms in a 1.49×103 g sample of strontium.
The number of atoms in 1.49×10³ g sample of strontium is 1.02×10²⁵ atoms
Avogadro's hypothesis1 mole of strontium = 6.02×10²³ atoms
But
1 mole of strontium = 87.62 g
Thus, we can say that:
87.62 g of strontium = 6.02×10²³ atoms
How to determine the atoms in 1.49×10³ g of strontiumWe can determine the number of atoms in 1.49×10³ g of strontium as illustrated below:
87.62 g of strontium = 6.02×10²³ atoms
Therefore,
1.49×10³ g of strontium = (1.49×10³ g × 6.02×10²³ atoms) / 87.62 g
1.49×10³ g of strontium = 1.02×10²⁵ atoms
Thus, 1.02×10²⁵ atoms are present in 1.49×10³ g of strontium
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HELP ME PLEASEEE WITH CHEMISTRY HOMEWORK
Answer:
Explanation:
11- d
12- dont know
13- c
14- d = 30
15- b =64
16- c = 34
17- positive= 19 protons , negative= 19electrons , neutral = 39 - 19 = 20 notrons
18- chlorine-35
because atomic mass (35.453) is close to (35)
Using the data in the table, determine the rate constant of the reaction and select the appropriate units.
A+2B⟶C+D
TRIAL---[A] (M)--- [B] (M)---RATE (M/s)
1 ---------0.360 ---0.360----0.0224
2 --------0.360----0.720----0.0224
3 --------0.720 ----0.360----0.0896
Order:
k=
Observation:
The rate is unaffected with respect to the concentration of B.
Answer:
k=0.0224 M/s
Explanation:
Give me Brainliest if that helped! :)
The rate constant of the reaction is 0.0224 m/s. the rate constant is denoted by symbol k. The velocity and direction of a chemical reaction are quantified in chemical kinetics by the reaction rate constant, or reaction rate coefficient, k.
What is rate constant ?The proportionality constant in the equation that defines the link between the rate of a chemical reaction and the concentrations of the reacting chemicals is known as the rate constant, also known as the specific rate constant.
The rate constant provides insight into the variables that affect a reaction's rate. The dependence of the molar concentration of the reactants on the rate of reaction may be determined by knowing the rate constant.
The rate constant provides insight into the variables that affect a reaction's rate. The dependence of the molar concentration of the reactants on the rate of reaction may be determined by knowing the rate constant.
Thus, option 2 is correct.
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How many hydrogen atoms are present in this molecule?
A: 6
B: 8
C: 9
D: 10
E: 13
A 51.0 mL portion of a 1.60 M solution is diluted to a total volume of 288 mL. A 144 mL portion of that solution is diluted by adding 147 mL of water. What is the final concentration? Assume the volumes are additive
A 51.0 mL portion of a 1.60 M solution is diluted to a volume of 288 ml. A 155 mL portion of that solution is diluted by adding 147 mL of water, the final concentration is 0.140 M.
so, in this dilution occurs two times:
Initial concentration is C1 = 1.60 M
concentration after first dilution C2 = ?
volume V1 = 51.0 ml
volume V2 = 288ml
the dilution formula :
C1 × V1 = C2 × V2
C2 = (C1 × V1 ) / V2
= ( 1.60 × 51.0 ) / 288
= 0.283 M
Now, for the second dilution :
V2 = 144 mL
V3 = 147mL + 144mL= 291 mL ( diluted by adding water)
C2 × V2 = C3 × V3
C3 = (C2 × V2) / V3
= ( 0.283 × 144 ) / 291
= 0.140 M
Thus, A 51.0 mL portion of 1.60 M solution is diluted to a volume of 288 ml. A 155 mL portion of that solution is diluted by adding 147 mL of water, the final concentration is 0.140 M.
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What is the job of a scientist why do scientits need government funding
Answer:
1. A scientist conducts and gathers research to gain knowledge in a particular area.
2. Many of the worlds problems include resources, energy, health, environment, climate, transportation, communication, etc. and will require solutions from science and engineering.
The picture shows a model of a helium atom and a model of a lithium atom. Which of the following statements is true about the lithium and the helium atoms? A. Helium has more protons, neutrons, and electrons. B. There is no difference between helium and lithium. C. Lithium has more protons, neutrons, and electrons. D. Lithium is much smaller than helium.
Answer:
C. Lithium has more protons, neutrons, and electrons.
Answer: C. Lithium has more protons, neutrons, and electrons.
Explanation:
Why does copper have a high thermal and electrical conductivity
Answer:
because it is good conductor of electricity
Would acetaminophen give a positive phenol test?
Since it contains a phenol group, acetaminophen will give a positive phenol test when ferric chloride is added. Salicylic acid remains unreacted and causes a color change when it reacts with ferric chloride.
What is phenol?Phenol is primarily used in the manufacture of phenolic resins as well as nylon and other synthetic fibers.
It is also used as a disinfectant and antiseptic, as well as in medicinal preparations such as mouthwash and sore throat lozenges.
Acetaminophen will give a positive phenol test when ferric chloride is added because it contains a phenol group. When salicylic acid reacts with ferric chloride, it remains unreacted and causes a color change.
Thus, it can be concluded that yes, positive phenol test can be taken in case of acetaminophen.
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Which option best describes the outer shell of the atoms in
Group 17 on this illustration of the Periodic Table?
O They have 7 protons.
OThey have 17 protons.
OThey have 7 electrons.
OThey have 17 electrons.
The option that best describes the outer shell of the atoms in Group 17 is they have 7 electrons.
What are the basic characteristics of group 17 elements?Group 17 elements such as chlorine, fluorine, etc have low bond dissociation energy due to their small atomic radius.
Basic characteristics include:
All the elements of group 17 have 7 electrons in its valence shell. These elements require one electron to finish their octet. They can complete their octet either by picking up an electron or sharing an electron.Thus, the option that best describes the outer shell of the atoms in Group 17 is they have 7 electrons.
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Graphite is a solid form of carbon that is commonly used in pencils. graphite breaks easily. What property of graphite makes it break easily.
The graphite is brittle in nature and this property makes the graphite to be break very easily or to make the graphite weak.
Graphite is a solid form of carbon that is commonly used in pencils. graphite breaks easily. What property of graphite makes it break easily?
Actually the graphite is naturally very brittle compound and the graphite can not be used as a material structure on its own due to its sheer planes.
The fact that why graphite is brittle is that the carbon atoms in the graphite are only bounded by the three strong covalent bonds in a two-dimensional 'layer lattice'.
The bonds inside the atoms of the carbon which is present in the layers of the graphite maybe strong but but the bonds that are formed by carbon atoms between layers are very weak, so that's why the graphite can be broken easily.
So we can conclude that the graphite is brittle in nature and this property makes the graphite to be break very easily or to make the graphite weak.
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Which atoms in the table are the same element and with what reasoning?
Atoms 2 and 3, because they have the same number of electrons.
All atoms are the same because they have the same number of neutrons.
Atoms 1 and 3, because the sum of all subatomic particles are equal.
Atoms 1 and 2, because they have the same number of protons.
The atoms that are the same element are atoms 1 and 2, because they have the same number of protons (option D).
What is an element?Element is one of the simplest chemical substances that cannot be decomposed in a chemical reaction or by any chemical means and made up of atoms all having the same number of protons.
The atoms of an element have the same number of protons, which is the atomic number.
According to the table given above, three atoms and their respective proton, electron and neutron number are given.
It can be said that atoms 1 and 2 are of the same element, because they have the same number of protons.
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How many grams of gold will fill up 5.00 cm3 of space if the density of gold is 19.3 g/cm3?
Round to the correct number of significant figures. Do not include the unit in the answer.
The gold will fill up 5.00 cm³of space if the density of gold is 19.3 g/cm³. Then the amount of gold filled in 5.00 cm³ of space is 96.5g.
What is density?Density is defined as the measurement of how tightly the material is packed together.
Density is defined as mass/volume.
The SI unit of density is gram/cubic centimeter.
Density can be expressed as
Density = mass/volume
As density is given as 19.3 gm/cm³ and volume is 5.00 cm³, then the mass can be calculated as
Mass = density x volume
= 19.3 x 5.00 = 96.5g
Thus, the amount of gold filled in 5.00 cm³ of space is 96.5g.
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Which of the following is true about the number of subatomic particles of the element Argon (Ar)?
a. It has 18 protons, 18 electrons, and 22 neutrons.
b. It has 18 protons, 18 electrons, and 42 neutrons.
c.It has 22 protons, 22 electrons, and 18 neutrons.
d. It has 22 protons, 22 electrons, and 22 neutrons.
Answer:
A
Explanation:
Complete the balanced dissociation equation for the compound below in aqueous solution. If the compound does not dissociate, write NR after the reaction arrow. Be sure to include the proper phases for all species within the reaction.
ZnCl2-
The balanced dissociation equation of the ionic compound ZnCl₂ is given below:
ZnCl₂ (aq)→ Zn²⁺ (aq) + 2 Cl⁻ (aq) What is a dissociation equation of a chemical reaction?A dissociation equation of a chemical reaction is a n equation which shows the products formed when an ionic substance is dissolved in an aqueous solution to produce ions.
A dissociation reaction results in the formation of ions and occurs only in ionic compounds
The dissociation of the ionic compound ZnCl₂ is shown below:
ZnCl₂ (aq)→ Zn²⁺ (aq) + 2 Cl⁻ (aq)From the equation above, the ionic compound zinc chloride is dissolved in water. The dissolution of the compound inn water results in the free dissociation or separation of the ions present in the crystal structure of the compound.
The compound dissociates to produce two moles of chloride ions and one mole of zinc (ii) ions. This is because the charge on the zinc ion is +2 while that on the chloride ion is -1.
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Which of the following are physical changes?
Making a shirt from cloth (physical)
ice melting (physical)
baking a cake (chemical)
burning wood (chemical)
theres two physical ones but i can only pick one answer
Answer: I believe its ice melting
Explanation: it would be ice melting because it can turn back into ice by itself with out any human doing anything to it.
How to balance NH3+NO=N2+H2O
Explanation:
NH₃+NO=N₂+H₂O;
NH₃+NO=N₂+6H₂O;
NH₃+6NO=N₂+6H₂O;
4NH₃+6NO=N₂+6H₂O;
4NH₃+6NO=5N₂+6H₂O.
how is phenol and ethanal distinguish
Alcohol is almost neutral in nature, whereas phenol has a weak acidic nature. The reaction with neutral FeCl3 distinguishes between ethanol and phenol.
Why phenol is acidic but ethanol is neutral?A phenoxide ion, or similar particle, is created when a phenol molecule loses its hydrogen ion. Since this phenoxide ion is resonance stabilized, its nature is acidic. However, when an ethanol molecule loses its hydrogen ion, it creates an ion.
Distinguish between alcohol and phenol and ethers :A saturated carbon atom bonds with a hydroxyl (-OH) group to produce alcohol. When the -OH group is substituted for a hydrogen atom in a benzene molecule, phenol is created. When an oxygen atom is joined to two alkyl or aryl groups, ether is created.
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QUESTION 8 1 POINT
Which of the following statements does not accurately describe the precision of a measurement?
Select the correct answer below:
The precision is a measure of the spread of expected values for a given measurement.
The precision describes the closeness of replicate measurements of the same property.
The precision can be quantified as the standard deviation of a set of data.
The trueness is a measure of how close a measurement is to an accepted value.
The statements 'The precision is a measure of the spread of expected values for a given measurement .' does not accurately describe the precision of a measurement .
Precision refers to how close measurements of the same item are to each other . Precision is independent of accuracy . That means it is possible to be very precise but not very accurate, and it is also possible to be accurate without being precise . The best quality scientific observations are both accurate and precise .
It is also define in one term as the quality or state of being precise .
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what is the final temperature of an 18.0 g aluminum sample if it is initially at 22.0 C and it absorbs 48.0 calories of heat energy? Note: The specific heat value for aluminum is 0.210 cal/g C.
The final temperature of an 18.0 g aluminum sample if it is initially at 22.0 C and it absorbs 48.0 calories of heat energy is 34.7°C.
How to calculate final temperature?The temperature of a substance can be calculated using the following formula:
Q = mc∆T
Where;
Q = quantity of heat absorbed or releasedm = mass of the substancec = specific heat capacity∆T = change in temperatureAccording to this question, an 18.0 g aluminum sample is initially at 22.0 C and it absorbs 48.0 calories of heat energy. The final temperature can be calculated as follows:
48 = 18 × 0.210 × {X - 22}
48 = 3.78x - 83.16
3.78x = 131.16
X = 34.7°C
Therefore, the final temperature of an 18.0 g aluminum sample if it is initially at 22.0 C and it absorbs 48.0 calories of heat energy is 34.7°C.
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How many kilograms of HNO3 are consumed to produce 112kg Ca(H2PO4)2 in this reaction?
Ca3(PO4)2 + 4HNO3 → Ca(H2PO4)2 + 2Ca(NO3)2 (Balanced equation)
Taking into account the reaction stoichiometry, 120.615 kg of HNO₃ are consumed to produce 112 kg Ca(H₂PO₄)₂.
Reaction stoichiometryIn first place, the balanced reaction is:
Ca₃(H₂PO₄)₂ + 4 HNO₃ → Ca(H₂PO₄)₂ + 2 Ca(NO₃)₂
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
Ca₃(H₂PO₄)₂: 1 moleHNO₃: 4 molesCa(H₂PO₄)₂: 1 moleCa(NO₃)₂: 2 molesThe molar mass of the compounds is:
Ca₃(H₂PO₄)₂: 314 g/moleHNO₃: 63 g/moleCa(H₂PO₄)₂: 234 g/moleCa(NO₃)₂: 164 g/moleThen, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction (being 1000 g= 1 kg):
Ca₃(H₂PO₄)₂: 1 mole ×314 g/mole= 314 grams= 0.314 kgHNO₃: 4 moles ×63 g/mole= 252 grams= 0.252 kgCa(H₂PO₄)₂: 1 mole ×234 g/mole= 234 grams= 0.234 kgCa(NO₃)₂: 2 moles ×164 g/mole= 328 grams= 0.328 kgMass of HNO₃ requiredThe following rule of three can be applied: If by reaction stoichiometry 0.234 kg of Ca(H₂PO₄)₂ is produced from 0.252 kg of HNO₃, 112 kg of Ca(H₂PO₄)₂ is produced from how much mass of HNO₃?
mass of HNO₃= (112 kg of Ca(H₂PO₄)₂× 0.252 kg of HNO₃)÷ 0.234 kg of Ca(H₂PO₄)₂
mass of HNO₃= 120.615 kg
Finally, 120.615 kg of HNO₃ are consumed to produce 112 kg Ca(H₂PO₄)₂.
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what is equivalent to 2ATM
Calcium carbide, CaC2, is manufactured by reducing lime with carbon at high temperature. (The carbide is used in turn to make acetylene, an industrially important organic chemical.)
CaO(s)+3C(s)→CaC2(s)+CO(g) ΔH=464.8kJ
Calculate the quantity of energy, in kJ, transferred when 0.432 mol carbon reacts with CaO(s).
The energy that is transferred by 0.432 mol carbon is 200.79 kJ.
What is the heat of reaction?We know that the heat of reaction refers to the heat that was evolved or absorbed when reactants combine to form a product. The heat of reaction is positive when heat is absorbed and it is negative when heat is evolved.
Given the fact that we have the reaction; [tex]CaO(s)+3C(s) -------- > CaC_{2} (s) + CO (g)[/tex]→Ca[tex]C_{2}[/tex](s)+CO(g) ΔH=464.8kJ We are now required to obtain the quantity of energy, in kJ, transferred when 0.432 mol carbon reacts with CaO(s).
Given that;
1 mole of CaO transfers 464.8kJ of energy
0.432 mol carbon transfers 0.432 mol * 464.8kJ /1 mole
= 200.79 kJ
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In the following Isotope Table, how would one find the letter J?
Add 40 and 44
Subtract 40 from 44
Multiply 40 by 44
Add 40 to the isotope's atomic numer
Answer:
A. Add 40 and 44
Explanation:
mass number = protons + neutrons
protons = electrons
so mass number = 40 + 44
Why is it difficult to precisely date samples from after the 1940's?
A. It is too close to the present to get an accurate reading from a half-life.
B. There aren't any radioactive isotopes that have a half-life short enough to date something that recent.
C. A major solar flare in the 1940's contaminated everything on the surface at that time with extra radioactivity.
D. Nuclear bombs contaminated the samples with more radioactivity.
It is difficult tp precisely date samples from after the 1940's is Nuclear bombs contaminated the samples with more radioactivity.
We use radioactive method to date the samples by using various radioisotopes and it gives a high degree of accuracy but this radioactive method may not work in future because of Nuclear bombs , nuclear reactors test started changing environment and this will lead to the difficulties in dating sample precisely.
Radiocarbon dating or carbon - 14 dating uses natural occurring radioisotope carbon - 14,It is used to determine the age of object from bones to plant fibers and wood, by the radiocarbon properties.
Thus , It is difficult tp precisely date samples from after the 1940's is Nuclear bombs contaminated the samples with more radioactivity.
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Find the value of x and y
Calculate the molarity of 143 grams of sucrose, C12H22O11, in 4.20 liters of solution.
Answer:
0.0996 M (3 s.f.)
Explanation:
Molarity is the number of moles per litre.
Let's find the number of moles of sucrose.
[tex]\boxed{\text{Moles= Mass}\div\text{Mr}}[/tex] , where Mr is the molecular weight of the compound.
[tex]\text{Mr of C}_{12}\text{H}_{22}\text{O}_{11}[/tex]
= 12(12)+22(1)+11(16)
= 342
Moles of sucrose
= 143 ÷342
= 0.41813 mol (3 s.f.)
This means that in 4.20L of solution, we have approximately 0.41813 moles of sucrose. We can now calculate the amount of sucrose in 1L of solution.
Molarity
= 0.41813 ÷4.2
= 0.099555 mol/L (5 s.f.)
= 0.0996 M (3 s.f.)
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Which statement describes a step in the formation of an ionic bond?
Answer:
Which statement describes a step in the formation of an ionic bond? An attraction occurs between two ions that have the same charge.
Explanation:
An analytical chemist measures the amount of Elements and in four samples of an unknown Substance :
An analytical chemist measures the amount of Elements and in four samples of an unknown Substance ;
as per the samples :
we have mass % of
[tex]E_1[/tex] in Sample 1 = 8.2g x 100/ 8.29 +18.99
= 30%
mass % [tex]E_1[/tex] in sample2 = 6.19 x 100/ 6.1 g +13.9 g
=30%
Similasly mass % of [tex]E_1[/tex]in sample 3 and sample are also 30%
Hence mass % [tex]E_2[/tex] in all samples are 70%
:. X is a pure substance
mass of sample x = 10.0g
mass of Element El = 30% of x
= 30 x 100g/ 100
= 3.og
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naturally occuring strontium consists of four isotopes, Sr-84, Sr-86,Sr-87 and ser-88 what is the average atomic mass of stronium
The average atomic mass of naturally occurring strontium which consists of four isotopes, Sr-84, Sr-86, Sr-87, and Sr-88 is 87.1 amu.
To determine average atomic mass,
we take average of weight of all of the isotopes of that element.
Molecular weight of -
Sr-84 = 83.9 amu
Sr-86 = 85.9 amu
Sr-87 = 86.9 amu
Sr-88 = 87.9 amu
Average = 83.9 + 85.9 + 86.9 + 87.9 = 86.15
4
We'll see the abundance of each isotope of strontium. Since the most abundant isotope of strontium is Sr-88 with 82.6% abundance. Therefore, the average atomic mass of strontium is closest to the mass of Sr-88, and the other isotopes are less than this mass.
Hence, the atomic mass of strontium is, 87.1 amu.
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