Answer: Steel wool turns from a gray color to a reddish color after it gets wet and then sits on a counter is a sign of chemical change.
Explanation:
A change that brings change in chemical composition of a substance is called a chemical change.
For example, Steel wool turns from a gray color to a reddish color after it gets wet and then sits on a counter is a chemical change.
This is because steel wool is mostly made up of iron and when iron becomes wet then in the presence of air it gets oxidized and therefore, it gets corroded.
This corrosion appears as reddish color of steel wool and it represents a chemical change has occurred in the steel wool.
Thus, we can conclude that steel wool turns from a gray color to a reddish color after it gets wet and then sits on a counter is a sign of chemical change.
Select the correct image.
The image shows the embryonic development of four different types of vertebrates. Which developmental path is most likely that of a lizard?
Answer:
what image?????
Explanation:
?
Answer:
2nd image/ image B
Why do you think certain countries favored military solutions to the great depression while other contries did not
Answer:
The answer is below
Explanation:
Certain countries like Germany under Adolf Hitler favored military solutions to the great depression because the government felt that having a mass production of military weapons and recruitment of unemployed people or citizens into the army would change the dire situation.
On the other hand, countries like the United States did not favor the military solutions but instead choose the NEW DEAL under Franklin D Roosevelt; the reason could be linked to their democratic culture, the isolation belief tendency.
A. Exothermic
B. Isothermic
C. Endothermic
Answer:
C. Endothermic
Explanation:
Since the products potential energy is higher than the reactants potential energy, it has abosrbed energy, thus making the graph endothermic.
5) How many Kilograms are in 12 L of Chlorine Gas?
Answer: 0.03798 kilograms
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given volume}}{\text {Molar Volume}}=\frac{12L}{22.4L}=0.535moles[/tex]
1 mole of chlorine gas [tex](Cl_2)[/tex] weighs = 71 g
Thus 0.535 moles of chlorine gas [tex](Cl_2)[/tex] will weigh = [tex]\frac{71}{1}\times 0.535=37.98g=0.03798kg[/tex] (1kg=1000g)
Thus there are 0.03798 kilograms in 12 L of chlorine gas.
what is the chemical name for Se8O7
Answer:
Selenium oxide
Explanation:
According to Chargaff's Rule, if a segment of DNA contains 60 cytosine bases out of a total of 300 bases how many thymine bases are in the segment?
Answer:
90 Thymine bases
Explanation:
Chargaff's rules states that in the DNA of any organism, the amount of purine and pyrimidine bases must be in a 1:1 ratio. This means that the amount of Adenine and Guanine bases (purines) should be equal with their complementary pairs of Thymine and Cytosine bases respectively (pyrimidines). (A = T) + (G = C) = 100
Hence, according to this question, if there are 60 cytosine bases, this means that there will be 60 Guanine bases. 60 C + 60 G = 120 pyrimidines
300 total bases - 120 pyrimidine bases = 180 purine bases.
180/2 = 90 equal bases of Adenine and Thymine. Hence, Thymine bases will be 90.
GIVING BRAINLIEST!!!!!!!
PLSSS HELPPP!!!!
Jody had a chicken sandwich and orange juice for lunch. What do you think happens to this food after being passed to the intestines?
A)Both the small and large intestine filter the food from harmful material before they pass into the blood stream.
B)The small intestine absorbs the nutrients into the blood stream and the large intestine absorbs the water.
C)The small intestine turns the food mixture into solid wastes and the large intestine absorbs the nutrients.
D)The small intestine passes oxygen into the food mixture and the large intestine releases it as waste.
Pls no links it’s annoying
Answer:
it's B
Explanation:
the small intestine is know to carrie out most of the digestive process absorbing almost all the nutrients and well the large intestine absorbs water. hope it helps :)
The balanced equation below represents a reaction between propane and oxygen. C3H8 + 5 O2 → 3 CO2 + 4 H2O According to this equation, which ratio of propane to oxygen is correct? 5 grams CO2 1 gram C3H8 3 moles CO2 1 mole C3H8 5 moles O2 1 mole C3H8 3 moles CO2 4 moles H2O
Answer:
5 moles O2 1 mole C3H8
Explanation:
In the question, it is mentioned about the ratio Propane and Oxygen. So the the ration will be 1:5 i.e, 5 moles of O2 1 mole C3H8. There is only one option which mentions both Propane and Oxygen and others doesn't.
What could be an electron configuration of Na in the excited state?
Answer:
The excited state electron configuration shows when an electron is excited and jumps into a higher orbital. For example, sodium in its excited state would have an electron configuration of 1s2 2s2 2p6 3p1, compared with its ground state of 1s2 2s2 2p6 3s1.
Explanation:
What is an Independent Variable (IV)? *
here's your answer dear friend❤❤
Convert 6.71 moles NH3 to number of molecules.
Answer: There are [tex]40.41 \times 10^{23}[/tex] molecules present in 6.71 moles of [tex]NH_{3}[/tex].
Explanation:
Given: Moles of [tex]NH_{3}[/tex] = 6.71 mol
According to the mole concept, 1 mole of every substance contains [tex]6.022 \times 10^{22}[/tex] molecules.
Therefore, molecules present in 6.71 moles are calculated as follows.
[tex]Molecules = moles \times 6.022 \times 10^{23}\\= 6.71 \times 6.022 \times 10^{23}\\= 40.41 \times 10^{23}[/tex]
Thus, we can conclude that there are [tex]40.41 \times 10^{23}[/tex] molecules present in 6.71 moles of [tex]NH_{3}[/tex].
Given the [H+] = 3.89x10^-7M, what is the pOH?
Answer:
7.59
Explanation:
A sample of crushed rock is found to have 4.81 x10^21 atoms of gold. How many moles of gold are present in this sample?
Answer:
0.8 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
We have
[tex]n = \frac{4.81 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{4.81}{6.02} \\ = 0.799003...[/tex]
We have the final answer as
0.8 molesHope this helps you
a link bot answered my question so let me ask again
Answer:
4 NH3 + 5 O2 = 4 NO + 6 H2O
Explanation:
Balance to have equal atoms on both sides.
What is the OH- ion concentration, in moles per liter, of an aqueous solution with a pH of 7?
A. 1 × 10-14
B. 1 × 10-7
C. 7
D. 14
Answer:
B
Explanation:
the pH scale is based on the function
1x10-14
So since pH is neutral the concentration of OH and H must be equal hence the only option in which the concetration would [OH]{H}= 1x10-14 would be when both are equal so it cannot be a or d and when they are expressed in concetration so the only option is B.
The pH of the solution can be used to give the relation between the pOH and the hydroxide ion concentration. The concentration of hydroxide ions is 1 ×10⁻⁷. Thus, option B is correct.
What is pOH?pOH is the measure of the hydroxide ion in the solution. The hydroxide concentration from pH is related as:
pH = - log [H⁺]
[H⁺] = 10⁻⁷
= 1 × 10⁻⁷
The hydroxide concentration from hydrogen concentration is calculated as:
[H⁺][OH⁻] = 1 × 10⁻¹⁴
[OH⁻] = (1 × 10⁻¹⁴) ÷ (1 × 10⁻⁷)
= 1 ×10⁻⁷
Therefore, option B. 1 ×10⁻⁷ is the hydroxide ion concentration.
Learn more about hydroxide concentration here:
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when do electrons release photons
Answer:
Later when they are older
Explanation:
brainliest/
On the pH scale higher numbers indicate ?
Answer:
Higher numbers indicate bases- not acidic/less acidic
Explanation:
Answer:
higher the ph number means stronger base
Explanation:
How does natural selection, or the concept of “survival of the fittest,” affect us?
Answer:
I hope this helps you! :)
Explanation:
Survival of the fittest" is a popular term that refers to the process of natural selection, a mechanism that drives evolutionary change. Natural selection works by giving individuals who are better adapted to a given set of environmental conditions an advantage over those that are not as well adapted.
What are carbohydrates?
A. a type of base
B. a type of glyceride
C. a type of macromolecule
D. a type of amino acid
Answer:
a
Explanation:
me say so
Answer:
C
Explanation:
What causes elements to react to each other
Answer:
One atom of each element is made up of protons, neutrons, and electrons. The number of electrons determines how an element reacts. The number of protons gives the element its identity. ... They react well with nonmetals because they can easily give up electrons to form ions.
The enthalpy of a reaction is -1207 kJ/mol. Which of the following best
describes this reaction?
Answer:
D. Exothermic
Explanation:
The enthalpy, ΔH, of a reaction is defined as the change in heat when a reaction occurs.
A reaction with ΔH > 0 is called endothermic and requires energy to be produced
A reaction with ΔH < 0 is called exothermic and produce energy when occurs (An example is the combustion of octane that produce energy that is used in engines to produce movement)
As the enthalpy of the reaction is -1207kJ/mol (ΔH < 0) the reaction is:
D. ExothermicIf a gas exerts 812 torr of pressure at a volume of 31 liters and the temperature of 30 degrees C, how many moles of gas are in the container?
Answer:
1.35 moles
Explanation:
Assuming the gas is ideal, we can solve this problem by using the following equation:
PV = nRTWhere:
P = 812 torr ⇒ 812 / 760 = 1.08 atmV = 31 Ln = ?R = 0.082 atm·L·mol⁻¹·K⁻¹T = 30 °C ⇒ 30 + 273.16 = 303.16 KWe input the data:
1.08 atm * 31 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 303.16 KAnd solve for n:
n = 1.35 molWILL MARK BRAINLEISTTTT
HELPPPPPP
Substitute symbols and formulas for names and write balanced equations for each of the
reactions described below.
a) When copper(II) carbonate is heated, it forms copper(II) oxide and carbon dioxide gas.
b) Ammonium nitrate decomposes to water and dinitrogen monoxide.
c) Barium hydroxide reacts with carbon dioxide to form barium carbonate and water.
d) Sodium reacts with water to produce sodium hydroxide and hydrogen gas.
Answer:
jkrifhcuhixjck
gvudd
Explanation:
dugucdsorfooggigj
a CUCO3(s) + ( I don't have the symbol on my phone ) delta CUo(s) + CO2(g)
b NH4NO3➡️ HNo3 + H2O
c. Ba(OH)2+CO2 ➡️ BaCO3+H20
d Na +H20 ➡️NaOH +h2
Explanation:
I think this should be it , I think that 8s the symbol for hydrogen gas if its not correct I'm sorry
Which best describes the role of the nephrons ?
Nephrons collect salts to be stored for later use by the body.
Nephrons signal the bladder to release excess urine.
O Nephrons transport urine to the bladder.
Nephrons restore the substances and water the body needs.
Answer:
c
Explanation:
edge 2021
Answer:
c
Explanation:
What type of wave has the SHORTEST wavelength and the highest frequency?
Answer:
The answer is gamma rays.
Explanation:
Gamma rays have the highest energies, the shortest wavelengths, and the highest frequencies on the electromagnetic spectrum.
If 125 mL of 0.56 MH2SO4, is diluted to a volume of 0.250 L, what is the molarity of the resulting solution?
Answer:
0.28M H2SO4
Explanation:
The molarity of a solution is defined as the ratio between the moles of the solute (In this case, H2SO4) and its volume in liters.
In the problem, the volume of the solution is increased from 125mL to 250mL. That means the solution is diluted:
250mL / 125mL = 2 times.
As the solution is diluted 2 times, the concentration is decreased in 2, that is:
0.56M / 2 =
0.28M H2SO4Detergent is an example of what type of compound?
A.) synthetic organic compound
B.) organic compound
C.) chlorofluorocarbon
Answer : A
Explanation : Surface-active compounds/agents (surfactants) Substances which have the effect of reducing the surface tension of a solvent, an example being a detergent/surfactant or soap dissolved in water. ... Both synthetic detergents and soaps are surfactants. Surfactants See "Surface-active compounds/agents".
According to the context, a detergent is an example of a synthetic organic compound.
What is a detergent?They are a group of synthetic organic compounds that have the property of lowering the surface tension of the liquids in which they are dissolved.
These contain surfactant substances that help in penetration, soaking, emulsification, dispersion, solubilization.
Therefore, we can conclude that according to the context, a detergent is an example of a synthetic organic compound.
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5. How much heat is evolved when 24.9 g of propanol (C3H7OH) is burned? ΔHcomb = −2010 kJ/mol
The heat is evolved when 24.9 g of propanol (C3H7OH) is burned is 834.15 J
To solve this question, First, we need to find the number of moles present in 24.9 g of propanol.
⇒ Formula
n = M/m................. Equation 1⇒ Where:
n = number of moles M = mass of propanolm = molar mass of propanolFrom the question,
⇒ Given:
M = 24.9 gm = (12×3)+(1×8)+16 = 36+8+16 = 60 g/mol⇒ Substitute these values into equation 1
n = 24.9/60n = 0.415 mol⇒ Finally the heat evolved is
Q = nΔHQ = 0.415(-2010)Q = -834.15 JHence, The heat evolved when propanol is burned is 834.15 J
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What is the single replacement reaction of Zinc + Lead(iv) Chloride
Answer:
[tex]2Zn+PbCl_4\rightarrow 2ZnCl_2+Pb[/tex]
Explanation:
Hello there!
In this case, when referring to single replacement reactions, it is crucial for us to figure out the formula of the starting reactants; thus, we know zinc is Zn and lead (IV) chloride is PbCl₄. In such a way, the reaction proceeds as follows:
[tex]Zn+PbCl_4\rightarrow ZnCl_2+Pb[/tex]
Which must be balanced as shown below:
[tex]2Zn+PbCl_4\rightarrow 2ZnCl_2+Pb[/tex]
Regards!
What is one difference between an electron and a neutron?
Answer: Neutron has no charge, electron has a charge and mass. Neutron occurs inside the nucleus where electron is seen outside the nucleus.
Explanation: