Answer:
D. A reaction or change in a substance that results in a different substance
Explanation:
Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances.
according to law of conservation of energy, amount of energy is constant. then why is energy in electric cells used up?
Answer:
it is because all energy are bound to use up according to the law of conversion of energy
how to find the number of neutrons
Answer:
For all uncharged atoms, the number of electrons equals the number of protons. The mass number 40 is the sum of protons and neutrons. To find the number of neutrons, subtract the number of protons from the mass number.
Answer:
mass number- protons
Explanation:
Value representing the number of protons in an atom
Answer:
6
Explanation:
This equation is balanced: N2+H2 -NH3
A. True
B. False
what is the median number of seeds that germinate at 32
Answer:65
Explanation:
It can be seen that the three methyl groups in camphor and isoborneol show up as separate peaks, whereas those in borneol overlap to where they almost appear as a single peak. Based on your knowledge of chemical shift factors, explain why this is so?
Answer:
isoborneol and camphor both have methyl groups that have different shielding zones with -OH and -C=O groups respectively.
Explanation:
Using the knowledge of chemical shift we can see that out of the three methyl groups in isoborneol, there are two methyl groups that are not influenced by the chemical Influence of the -OH functional group while one of the methyl groups is influenced by the -OH functional group.
For Camphor, two out of the three methyl groups are in shielding zones of the Carbonyl group, -C=O. While the last of the three methyl groups is out of the shielding zones of Carbonyl group, -C=O.
Which part of an atom is gained, lost, or shared during a chemical reaction? (2 points)
оа
Electron
Oь
Proton
ос
Neutron
Od
Nucleus
Answer:
a) electron
Explanation:
Answer:
a
Explanation:
i took the test
A solution of potassium sulfide is mixed with a solution of magnesium bromide. Identify the two possible products.
Answer:
Magnesium sulfide and potassium bromide.
Explanation:
Hello!
In this case, for the two mentioned solutions, which are composed by both potassium sulfide (K2S) and magnesium bromide (MgBr2), the following chemical reaction would be carried out:
[tex]K_2S+MgBr_2\rightarrow MgS+KBr[/tex]
However, due to the discrepancy in the atoms of bromine and potassium, the balanced chemical equation should be:
[tex]K_2S+MgBr_2\rightarrow MgS+2KBr[/tex]
Whereas the products are magnesium sulfide and potassium bromide which are both soluble in water.
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What is the general rule to name ionic compounds form by a cation and a polyatomic ion, write two examples.
Answer:
Rule 1. The cation is written first in the name; the anion is written second in the name.
Rule 2. When the formula unit contains two or more of the same polyatomic ion, that ion is written in parentheses with the subscript written outside the parentheses.
examples: ammonium ion and hydrogen carbonate
Explanation:
hope this helps
Which statement is true about S-waves?
A They are the slowest selsmic waves.
B They travel only through solids.
They are the first to be detected by
seismometers.
D They can travel through solids and
liquids.
please help
Answer:
B They travel only through solids.
Explanation:
Seismic s-waves are also known as secondary or shear-waves. They are elastic waves that travels within a body.
At a seismic station, they are the second set of waves to arrive after the primary - waves. They can only pass through solid bodies as fluids cannot be sheared. The above mentioned property makes them very useful in determining the interior property of the earth. They are not the slowest seismic waves.The first person who suggested that matter was made up of atoms was the Greek philosopher ____________________ .
Answer:
Democritus
Explanation:
Answer:
Democritus of Abdera
Explanation:
Dan bikes 10 km west and then bikes another 5 km west. What is Dan's
velocity if it takes him 45 minutes?
A. 0.1 km/min west
B. 3 km/min west
C. 0.3 km/min west
D. 9 km/min west
(I AM GIVING BRAINLIEST!!!!)
Before there is a transfer of charges between objects, they are uncharged. What does this mean?
A) There are more positive charges than negative charges.
B) There are more negative charges than positive charges.
C) The positive and negative charges are equal.
D) The positive and negative charges do not exist.
Answer:
C) The positive and negative charges are equal.
Explanation:
Ions can be made by single element or covalently bonded group of elements. The covalently bonded group of elements is called polyatomic ions or polyatomic atoms. The correct option are option C.
What is Ions?Any species that contain charge whether it is positive charge or negative charge is called ions. The example of polyatomic ions are sulfate, phosphate, nitrate etc.
Cation is the species that loose electron and attain positive charge while anion is a species which gain electron and attains negative charge so when anion and cation combine in fixed ration the the overall charge of the molecule is zero that is molecule is neutral, the charge over cation and anion is also called oxidation state.
Before there is a transfer of charges between objects, they are uncharged as the positive and negative charges are equal.
Therefore the correct option are option C.
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1. As elements go across from left to right in a period,
they hold their electrons more tightly, because they
have more protons in the nucleus attracting the
orbitting electrons in the electron cloud. So across a
period, does atomic radius increase or decrease?
Answer:
decrease.
Explanation:
WHY? - As you go across a period, electrons are added to the same energy level. ... The concentration of more protons in the nucleus creates a "higher effective nuclear charge." In other words, there is a stronger force of attraction pulling the electrons closer to the nucleus resulting in a smaller atomic radius.
Calculate the value of ni for Hydrogen if a violet line from the Balmer series has a recorded wavelength of 410 nm.
Solution :
Given that the violet line from Balmer series having a recorded wavelength of 410 nm. As the recorded wavelength is 410 nm we know, the wavelength range of violet light is 380 nm -450 nm. So the 410 nm is corresponding to violet light wavelength.
We know, among all the series of lines spectrum of [tex]$H_2$[/tex] atom, only the Balmer series are in visible range. For Balmer series, the equation of wavelength associated with the e-transition of n = 2 orbit to n > 2 is
[tex]$\frac{1}{\lambda}=R\left[\frac{1}{2^2}-\frac{1}{n^2}\right]$[/tex]
where, R = Rydberg constant = 109678 per cm
λ = wavelength
Here the recorded λ = 410 nm = [tex]$410 \times 14^{-7} \ cm$[/tex]
∴ [tex]$\frac{1}{410 \times 10^{-7}}=109678\left[\frac{1}{2^2}-\frac{1}{n^2}\right]$[/tex]
[tex]$\frac{1}{2^2}-\frac{1}{n^2}=\frac{1}{410 \times 10^{-7}\times 109678}$[/tex]
[tex]$\frac{1}{4}-\frac{1}{n^2}=0.222$[/tex]
[tex]$\frac{1}{n^2}=\frac{1}{4}-0.222$[/tex]
[tex]$n^2=\frac{1}{0.0276}$[/tex]
[tex]$n^2=36.2$[/tex]
[tex]$n^2 $[/tex] ≈ 36
n = ±6
Here, n is the principle quantum number. It cannot be negative, so the value of n = 6 for hydrogen atom if the violet line from Balmer series that has a recorded wavelength of 410 nm.
The value of n for the Hydrogen transition in the Balmer series with the wavelength 410 nm has been 6.
The principal quantum number in the Balmer series transition has been given by n. The minimum transition for the Balmer series has been from the 2 energy level.
The expression for the wavelength transition can be given by:
[tex]\rm \dfrac{1}{\lambda}\;=\;R\;[\dfrac{1}{2^2}\;-\;\dfrac{1}{n^2} ][/tex]
[tex]\lambda[/tex] = Wavelength = 410 nm = 410 [tex]\rm \times\;10^-^7[/tex] cm
R = Rydbreg constant = 109678/cm
[tex]\rm \dfrac{1}{410\;\times\;10^-^7}\;=\;109678\;[\dfrac{1}{2^2}\;-\;\dfrac{1}{n^2} ][/tex]
[tex]\rm \dfrac{1}{410\;\times\;10^-^7\;\times\;109678}\;=\;\;[\dfrac{1}{2^2}\;-\;\dfrac{1}{n^2} ][/tex]
[tex]\rm 0.222\;=\;\;[\dfrac{1}{2^2}\;-\;\dfrac{1}{n^2} ][/tex]
[tex]\rm 0.222\;=\;\;[\dfrac{1}{4}\;-\;\dfrac{1}{n^2} ][/tex]
[tex]\rm 0.222\;-\;\dfrac{1}{4}\;=\;\dfrac{1}{n^2}[/tex]
[tex]\rm n^2\;=\;36.2[/tex]
n = 6
The value of n for the Hydrogen transition in the Balmer series with the wavelength 410 nm has been 6.
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which sample is a pure substance
a. a test tub of zinc oxide
b. a container of zinc and oxygen
c. A flask of Pondwater
d. A jar of soil
A image of a drag race car has long arrow A pointing up, medium length arrow B pointing down, medium length arrow C pointing forward and left, and short arrow D pointing backward and right. Which arrow represents the force of gravity acting upon the car? Which arrow represents the normal force on the car? Which arrow represents the applied force on the car when the driver steps on the gas pedal?
Which arrow represents the force of gravity acting upon the car?
✔ B
Which arrow represents the normal force on the car?
✔ A
Which arrow represents the applied force on the car when the driver steps on the gas pedal?
✔ C
What formula do you use to calculated density?
O Volume X Mass = Density
O Volume + Mass = Density
O Mass + Volume= Density
Mass - (Volume) x Matter = Density
Cle
Answer:
7 AM was the first to be the best Friend and a friend and I have seen the target market share of a million dollars and Diamond.
Answer:Density, mass of a unit volume of a material substance. The formula for density is d = M/V, where d is density, M is mass, and V is volume. Density is commonly expressed in units of grams per cubic centimetre.
Explanation:
The value of ΔH° for the reaction below is -336 kJ. Calculate the heat (kJ) released to the surroundings when 23.0 g of HCl is formed. CH4(g) + 3Cl2(g) → CHCl3(l) + 3HCl(g)
The heat (kJ) released to the surroundings : -70.56 kJ
Further explanationReaction
CH₄(g) + 3Cl₂(g) → CHCl₃(l) + 3HCl(g) ΔH°=-336 kJ
For 3 mol HCl formed ⇒ ΔH°=-336 kJ
23.0 g of HCl :
mol[tex]\tt \dfrac{23}{36.5}=0.63[/tex]
Heat released for 0.63 mol HCl :
[tex]\tt \dfrac{0.63}{3}\times -336=-70.56~kJ[/tex]
The heat (kJ) released to the surroundings at the given equation is 70.7KJ.
The calculation is as follows:We know that
[tex]Moles\ or\ HCl\ formed = mass \div molar\ mass\\\\= 23.0\div 36.46[/tex]
= 0.631 mole
Since energy should be related at the time when 3 moles of HCI should be generated = 336 K
Now energy released is
[tex]= (336\div 3)\times 0.631[/tex]
= 70.65 kJ
Hence we can conclude that heat released to the surrounding is 70.7 kJ.
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________ is a strong and flexible material found in a skeleton.
Answer:
Cartilage
Explanation:
Be careful, if you grind down your cartilage it pinches your nerves and can cause serious problems
A blank solution containing only solvent had an absorbance of 0.029 at the same wavelength. Find the molar absorptivity of compound A.
Answer:
The question is incomplete. Searching in google I found: A 3.96x10⁻⁴ M solution of compound A exhibited an absorbance of 0.624 at 238 nm in a 1.000-cm cuvette. A blank solution containing only solvent had an absorbance of 0.029 at the same wavelength. Find the molar absorptivity of compound A.
The molar absorptivity of compound A is 1502.5 M⁻¹cm⁻¹.
Explanation:
The question is incomplete. Searching in google I found: A 3.96x10⁻⁴ M solution of compound A exhibited an absorbance of 0.624 at 238 nm in a 1.000-cm cuvette. A blank solution containing only solvent had an absorbance of 0.029 at the same wavelength. Find the molar absorptivity of compound A.
The absorbance (A) is given by:
[tex] A = \epsilon cl [/tex]
Where:
c: is the concentration of compound A = 3.96x10⁻⁴ M
ε: is the molar absorptivity of compound A =?
l: is the pathlength = 1 cm
[tex]A_{s}[/tex]: is the absorbance of the solution= 0.624
[tex]A_{b}[/tex]: is the absorbance of the blank solution= 0.029
First, we need to find the absorbance of compound A:
[tex] A = A_{s} - A_{b} = 0.624 - 0.029 = 0.595 [/tex]
Now, we can calculate the molar absorptivity of compound A:
[tex] \epsilon = \frac{A}{cl} = \frac{0.595}{3.96 \cdot 10^{-4} M*1 cm} = 1502.5 M^{-1}cm^{-1} [/tex]
Therefore, the molar absorptivity of compound A is 1502.5 M⁻¹cm⁻¹.
I hope it helps you!
Starch and glycogen
are both polysacharides.
True or false
Analyze how water affects mass movements by using two examples of mass
movement.-
Answer:
Types Descriptions
Flows occur when soil or rock acts like a liquid
Slumps a slice of material that moves as one piece along a curved surface
Landslides made up of unconsolidated rock; includes rockslides and avalanches
Creeps material that moves slowly down gently sloping areas
Explanation:
Googled it.
Water can affect mass movements by reducing the friction along a sliding surface and can also allow particles to slide past each other easily.
Mass movement refers to the transfer of rocks and solid downslope as a result of gravity. Mass movement is the relocation of surface material such as solid or rock from a point along a slope to a position that's further down the slope.
It should be noted that water triggers mass movement. This is done as water fills the pores that are in the sediments, this then allows the particles to slide past each other easily.
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Which of the following can be predicted using the activity series?
Speed of an acid-base reaction
Speed of a double replacement reaction
Possibility of a double replacement reaction
Possibility of a single replacement reaction
Answer:
Possibility of a single replacement reaction
Explanation:
The activity series of element can be used to predict the possibility of a single replacement reaction.
A single replacement reaction is one in which one substance is replacing the other. The replacement of a metallic ion in solution by a metal atom higher in the activity series than the metal in solution falls into this category of reactions. The relative position of the two elements in the activity series provides the driving force for this kind of reaction. If the element to replace the other is more reactive, the reaction will occur. If it is less reactive, the reaction will not occur.Answer:
Possibility of a single replacement reaction
Explanation:
how many moles of hydrogen are needed to produce 8 moles of methane CH4? C + H2-> CH4
Answer:
20 mol H₂
General Formulas and Concepts:
Chem
StoichiometryExplanation:
Step 1: Define
RxN: C + H₂ → CH₄
8 moles CH₄
Step 2: Balance RxN
C + 2H₂ → CH₄
Step 3: Stoichiometry
[tex]8 \ mol \ CH_4(\frac{2 \ mol \ H_2}{1 \ mol \ CH_4} )[/tex] = 16 mol H₂
Step 4: Check
We are given 1 sig fig. Follow sig fig rules.
16 mol H₂ ≈ 20 mol H₂
What is the parent chain name of the hydrocarbon below?
a. methane
b. heptane
c. hexane
d. ethane
e. butane
Answer:
Option B. Heptane
Explanation:
To obtain the parent name of the above compound, all we need to do is to locate the longest continuous carbon chain.
The longest continuous carbon chain of the above compound is 7.
Next, we shall also consider the chain if there is any double or triple bond.
From the diagram given above, no double or triple bond is present.
Finally, the parent name of the compound is heptane since the longest continuous carbon chain is 7 and no double or triple bond is present in the compound.
What state of matter is hydrogen?
Answer:
its a gas
Explanation:
Hydrogen is the chemical element in the periodic table that has the symbol H and atomic number 1. At standard temperature and pressure it is a colorless, odorless, non-metallic, univalent, highly flammable diatomic gas. Hydrogen is the lightest and most abundant element in the universe.
In the given question, the state of matter of Hydrogen is gas in nature.
A state of matter is one of the four distinct forms in which matter can exist as solid, liquid, gas, and plasma.
Hydrogen is a chemical element that occurs naturally as a gas at standard temperature and pressure (STP). It is the lightest and most abundant element in the universe and is found in stars, gas giants, and other celestial bodies.
It is also used in various industrial processes, such as the production of ammonia and methanol, and as a fuel source in fuel cells.
Therefore, hydrogen is in the gaseous state at room temperature and normal atmospheric pressure.
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Sodium, potassium, and cesium belong to which group?
inner transition metals
halogens
alkali metals
Answer:
Alkali Metals
Explanation:
10 m/s to 80 m/s in 5 seconds
900 mph................
Answer:
a = 0.8 m/s/s
Vav = 45m/s
Explanation:
Vav = [tex]\frac{Vi + Vf}{2\\}[/tex]
Vav = [tex]\frac{10 +80}{2}[/tex]
Vav = 45m/s
a = [tex]\frac{v}{t}[/tex]
a = [tex]\frac{4m/s}{5s}[/tex]
a= 0.8m/s/s
A sample of hydrogen sulfide, H2S, has a mass of 35.50 g. Calculate the number of hydrogen sulfide molecules in the sample.
Answer:
Number of hydrogen sulfide molecule = 5.7672 x 10²³ (Approx)
Explanation:
Molar mass of H2S = (1x2) + 32 = 34 g
Total number of molecule = 34 / 35.50
Total number of molecule = 0.9577
Avogadro's number = 6.022 x 10²³
Number of hydrogen sulfide molecule = 0.9577 x 6.022 x 10²³
Number of hydrogen sulfide molecule = 5.7672 x 10²³ (Approx)