the answer is is is is is is is is is is is is is is
It’s a science question
Why can't more than one variable be changed during an experiment?
O You need to make sure your results match your hypothesis.
O Changing two or more variables makes it difficult to find a cause and effect relationship.
O Change two or more variables would take longer.
O Changing two or more variables would make the experiment more precise.
Answer:
Changing two or more variables makes it difficult to find a cause and effect relationship.
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)
How many milligrams are in 2.89 x 1024 CO2 molecules?
Answer:
2,959.36
Explanation:
There are 2959.36 milligrams present in 2.89 x [tex]10^{24}[/tex] CO2 molecules.
What is molecule?The smallest component of a substance which possesses both its chemical as well as physical characteristics. One or even more atoms make up molecules.
What is milligrams?Such a measure of mass as well as weight that weighs 0.0154 grains or one-thousandth of a gram.
Calculation of milligram in CO2 molecule.
Mass = No. of molecule / molar mass.
Molar mass = 44.02 g/mol.
Mass = 2.89 x [tex]10^{24}[/tex] /[tex]6.023 * 10^{23}[/tex]× 44.02 g/mol.
Mass = 2959.36 milligrams
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what is the resonance structure of ch3
Answer:
For the CH3- structure use the periodic table to find the total number of valence electrons for the CH3- molecule. Once we know how many valence electrons there are in CH3- we can distribute them around the central atom with the goal of filling the outer shells of each atom.
In the Lewis structure of CH3- structure there are a total of 14 valence electrons.
Also note that you should put the CH3- Lewis structure in brackets with as 1- on the outside to show that it is an ion with a negative one charge.
----- Steps to Write Lewis Structure for compounds like CH3- -----
1. Find the total valence electrons for the CH3- molecule.
2. Put the least electronegative atom in the center. Note: Hydrogen (H) always goes outside.
3. Put two electrons between atoms to form a chemical bond.
4. Complete octets on outside atoms.
5. If central atom does not have an octet, move electrons from outer atoms to form double or triple bonds.
Lewis Structures, also called Electron Dot Structures, are important to learn because they help us understand how atoms and electrons are arranged in a molecule. This can help us determine the molecular geometry, how the molecule might react with other molecules, and some of the physical properties of the molecule (like boiling point and surface tension).
Explanation:
CH3CNO can be represented by at least three different but valid Lewis structures called resonance forms, or resonance structures, shown below.
Is a compound a mixture or a pure substance
Answer:
A compound is a pure substance.
What is the mass of some honey that has a volume of 120.8 fl oz and a density of 1.38 kg/L?
Answer:
166.704
Explanation:
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.
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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If a aluminum cube had a mass of 20g and the length of each side was 2cm between what to liquids would it float?
Answer:
density=20/8 g/cc=2.5 g/cc
Mercury is more dense, so aluminum will float on it. Water is less dense, so the aluminum will be below water.
Aluminum will float atop mercury because it is more dense than it. Due to water's lower density, the metal will lie below the surface.
What is density?Density is defined as the measure of how densely a material is packed together.
It can also be defined as the mass of a solid substance per unit volume.
Density is important because it enables us to predict which compounds will float and which will sink in a liquid, density is a crucial notion. As long as an object's density is lower than the liquid's density, it will often float.
The term "density" refers to the relationship between a substance's mass and the volume it takes up in space. The mass, size, and arrangement of an object's atoms influence its density.
Density can be expressed as
Density = mass / volume
There are two types of density.
Absolute densityRelative densityThus, aluminum will float atop mercury because it is more dense than it. Due to water's lower density, the metal will lie below the surface.
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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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Identify the labeled structures. A: B: B C: < A D: ✓ > E: D AVIS Det E с
please I need your help and fast so as soon as you seen this answer please I will list brainlyist
Answer:
ahhh i d kkkkk im so so so so sorry
Explanation:
28.5 g of iron shot is added to a graduated cylinder containing 45.50 mL of water. The water level rises to the 49.10 mL mark. From this information, calculate the density of iron.
HELLPPP CAN SOMEONE SOLVE THIS???
Answer:
Density if iron shot = 7.92 g/ml (2 sig. figs.)
Explanation:
By definition, density is mass per unit volume. That is,
Density (D) = mass(m)/Volume(V)
mass(m) = 28.5g (given)
Volume(V, of iron shot) = 49.10ml - 45.5ml = 3.6ml
Substitutuing into D = m/V = 28.5g/3.6ml = 7.9166667 g/ml (calc.ans)
≅ 7.92 g/ml (2 sig. figs.)
Hope this 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
Aluminium sulphate is organic or inorganic compound
Answer:
Aluminium sulphate is an inorganic compound.
Which substances will make a salt when combined?
Vinegar and soda
Soda and wine
Detergent and ammonia
Fertilizer and vinegar
Answer:
vinegar and soda
Explanation:
Mixing baking soda (sodium bicarbonate) and vinegar (acetic acid) causes a chemical reaction that produces a salt (sodium acetate) and water, as well as carbon dioxide gas.
Answer:
Fertilizer and vinegar
Explanation:
Fertilizer is a base, and vinegar is an acid. Salt is made when you combine a base and an acid. Plus, I got a 100% on the test and this was my answer.
the pH of soil X is 7.5 while that of soils Y is 4.5 which of the two coils should be treated with powered talked to adjust its PH
Answer:
Soils Y
Explanation:
• The soils with lower pH are acidic so they react readily with powdered.
[tex].[/tex]
Answer:
SOIL Y
the soil with lower ph are acidic
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:
What is a polyprotic buffer?
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.
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
classify each of these reactions pb(no3)2+nicl2=pbcl2+ni(no3)2
The reaction Pb(NO3)2(aq) + NiCl2(aq)---------> PbCl2(s) + Ni(NO3)2(aq) is a precipitation reaction.
A chemical reaction is said to occur when two or more substances are combined to produce new substances. Chemical reactions are classified based on the kind of change taking place in the reaction.
In the reaction;
Pb(NO3)2(aq) + NiCl2(aq)---------> PbCl2(s) + Ni(NO3)2(aq)
We can see that a solid is formed when lead II nitrate reacts with nickel II chloride. This is a precipitation reaction.
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can anyone heelp me pls pls
Answer:
Lotion=liquid
suspension=semisolid
capusule=solid
Explanation:
6. What is true about Calcium (Ca)?
A. It is a very unreactive metal.
B. It is reactive and is found with nonmetals in nature.
C. naturally uncombined with other elements.
D.It is a very reactive nonmetal.
Answer:
C. naturally uncombined with other elements.
Explanation: Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air.
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.
Elements in the alkaline earth metal family of the periodic table
have
electronegativity values than elements in the
halogen family of the periodic table.
Answer:Lower
Explanation:
( just had the question on ck12.)
Elements in the alkaline earth metal family of the periodic table have lower electronegativity values than elements in the halogen family of the periodic table as they have less electrons in their valence shell.
What is periodic table?Periodic table is a tabular arrangement of elements in the form of a table. In the periodic table, elements are arranged according to the modern periodic law which states that the properties of elements are a periodic function of their atomic numbers.
It is called as periodic because properties repeat after regular intervals of atomic numbers . It is a tabular arrangement consisting of seven horizontal rows called periods and eighteen vertical columns called groups.
Elements present in the same group have same number of valence electrons and hence have similar properties while elements present in the same period show gradual variation in properties due to addition of one electron for each successive element in a period.
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. 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
Which one is location 3 in___
Arm
Center
I CANT DELETE THE ANSWER, SO HERE.
Acetone [(CH3)2C=O], a simple ketone is commonly used to make products like nail polish remover and paint remover. Draw a picture showing the orbitals involved in the and bonds including its lone pairs.
Carbon and oxygen atoms in (CH3)2C=O form sigma and pi bonds. The pi bonds are formed using unhybridized p orbitals.
Acetone (CH3)2C=O contains the carbonyl group (C=O). Carbon is bonded to oxygen via a double bond as shown in the orbital structure. The carbon atom is also bonded to two methyl groups.
The central carbon atom is sp2 hybridized as well as the oxygen atom in acetone. The pi bond is formed by the overlap of unhybridized p orbitals on both carbon and oxygen atoms. The sigma bonds are formed using the sp2 hybridized carbon atoms on carbon and oxygen.
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You 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
Calculate the moles of calcium oxalate formed from 5 grams of potassium oxalate (molar mass 184.24 g/mol) the mole mole ratio from the balanced equation is 2.1 potassium oxalate to calcium oxalate
5 g of potassium oxalate react to produce 0.03 moles of calcium oxalate.
Calcium oxalate (CaC₂O₄) is obtained by the reaction of 5 g of potassium oxalate (K₂C₂O₄).
We can calculate the moles of CaC₂O₄ obtained considering the following relationships.
The molar mass of K₂C₂O₄ is 184.24 g/mol.The mole ratio of K₂C₂O₄ to CaC₂O₄ is 2:1.[tex]5 g K_2C_2O_4 \times \frac{1molK_2C_2O_4}{184.24gK_2C_2O_4} \times \frac{1molCaC_2O_4}{2molK_2C_2O_4} = 0.03molCaC_2O_4[/tex]
5 g of potassium oxalate react to produce 0.03 moles of calcium oxalate.
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