Answer:
न्द्न्द्ज्द्ज्फ्ज्फ्ज
Pls someone help me with this question pls
Answer:
D
Explanation:
A student dissolves 10.3 g of potassium chloride (KCI) in 200. g of water in a well-insulated open cup. She then observes the temperature of the water fall from 22.0 °C to 19.0 °C over the course of 6.8 minutes.
KCI(8) → K+ (aq) + Cl- (aq)
You can make any reasonable assumptions about the physical properties of the solution. Be sure answers you calculate using measured data are rounded to the correct number of significant digits.
Required:
Is this reaction exothermic, endothermic, or neither?
Answer:
Endothermic.
Explanation:
Hello there!
In this case, it is possible to answer to the requested question "Is this reaction exothermic, endothermic, or neither?" by looking at the temperature change; thus, since the temperature is diminished from 22.0 °C to 19.0 °C, it is possible to realize that the dissociation reaction:
KCI(8) --> K+ (aq) + Cl- (aq)
Is endothermic as it absorbs heat and therefore the solution gets cooled down. Now for any calculation regarding the heat of reaction, it'd be necessary to assume that the solution has a specific heat equal to the water as the former is mostly composed by the latter and the amount of KCl does not modify the solution significantly.
Best regards!
Why does a red object appear red?
O A. It reflects light of wavelengths other than red.
OB. It absorbs light of red wavelengths.
O C. It absorbs light of wavelengths other than red.
O D. It reflects infrared radiation.
Right answers only for brainly
Answer:
Objects appear different colours because they absorb some colours (wavelengths) and reflected or transmit other colours. ... For example, a red shirt looks red because the dye molecules in the fabric have absorbed the wavelengths of light from the violet/blue end of the spectrum
A red object appear red because it absorbs light of wavelengths other than red. Therefore, option C is correct.
What is wavelength ?The distance between identical points (adjacent crests) in adjacent cycles of a waveform signal propagated in space or along a wire is defined as the wavelength. This length is typically specified in wireless systems in meters (m), centimeters (cm), or millimeters (mm) (mm).
A transverse wave's wavelength is defined as the distance between two adjacent crests. A longitudinal wave's wavelength can be calculated as the distance between two adjacent compressions.
The wavelengths that are reflected or transmitted are what we see as colors. A red shirt, for example, appears red because the dye molecules in the fabric have absorbed light wavelengths from the violet/blue end of the spectrum. The only light reflected from the shirt is red light.
Thus, option C is correct.
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What is the mass in grams of 8.65 mol C8H18?
Answer in standard notation to zero decimal places.
PLEASE HELP THIS IS DUE AT 11:59 AT MIDNIGHT AND IM FREAKING OUT
Answer:
m = 998 g
Explanation:
Hello there!
In this case, according to the definition of the molar mass as the mass of one mole of the compound, it is possible to state the 1 mole of C8H18 has a mass of 114.26 grams; therefore, the mass in 8.65 moles turn out to be:
[tex]m=8.65mol*\frac{114.26g}{1mol}\\\\m=998g[/tex]
In agreement to the notation requirement.
Best regards!
A gas has a volume of 10 L at 200 K and a pressure of 1.5 atm . What would the volume of the gas be at 300 K and 2atm of pressure ?
Answer:
jeyjeyjetnetney
Explanation:
thmrhmrhmrum
The addition, removal, or substitution of nitrogenous bases in a DNA molecule may be caused by . Synapsis C. Disjunction B. Hybridization D. Mutation
Answer:
D. Mutation
Explanation:
Mutation is any change or alteration that occurs to the nucleotide sequence of a gene induced during DNA replication or by mutation-causing substances called MUTAGENS.
Mutation can be in the form of addition, removal, or substitution of nitrogenous bases in a DNA molecule. For example, in an original DNA sequence as follows: GAT ATC TGA, the following mutation can occur:
Addition: GAT ATC CTG A
Removal: GAT ATT GA
Substitution: GAT CTC TGA
how many molecules of sodium chloride are in 2.5 moles??
Answer:
1.5x1024
Explanation:
It takes 45.60 mL of a 0.225 M hydrochloric acid solution to react completely with 25.00 mL of calcium hydroxide in this reaction below, what is the molar concentration of the calcium hydroxide solution?
2HCl(aq) + Ca(OH)2(aq)!CaCl2(aq) + 2H2O(l)
Given :
It takes 45.60 mL of a 0.225 M hydrochloric acid solution to react completely with 25.00 mL of calcium hydroxide in the given reaction.
2HCl(aq) + Ca(OH)2(aq) --> CaCl2(aq) + 2H2O(l)
To Find :
The molar concentration of the calcium hydroxide solution.
Solution :
From given equation 2 mole of hydrochloric acid react with 1 mole of calcium hydroxide.
So,
[tex]2M_1V_1 = M_2V_2\\\\2\times 0.225 \times 45.60 = M_2 \times 25 \\\\M_2 = \dfrac{20.52}{25}\\\\M_2 = 0.8208 \ M[/tex]
Therefore, molar concentration of the calcium hydroxide solution is 0.8208 M.
Answer:
Molar concentration of the calcium hydroxide solution = 0.2052 M
Explanation:
Volume of HCl = 45.60 mL = 0.0456 L
Molar concentration of HCl = 0.225 M
Volume of Ca(OH)2 = 25.00 mL = 0.025 L
No. of moles of HCl = (0.225 M)*(0.0456 L) = 0.01026 mol
As we know
2 moles of HCl require 1 mole of Ca(OH)2, hence, .01026 moles of HCl will need 0.5*(0.01026) = 0.00513 moles of Ca(OH)2
Molar concentration of Ca(OH)2 = [(0.00513 mol)/(0.025 L)] = 0.2052 M
does anyone know how to do this?
Answer:
nah
Explanation:
URGENT A gas occupies a volume of 2.4 L at 0.14 ATM. What volume will the gas occupy at 0.84 ATM ?
a
0.28 L
b
14 L
c
0.40 L
d
2.5 L
Answer:
c 0.40 L
Explanation:
Calculate by using Boyle's Law P₁V₁=P₂V₂
(0.14atm)(2.4L) = (0.84atm)(V₂)
0.336 atmL = (0.84atm)(V₂)
V₂ = 0.336 atmL/0.84atm
V₂ = 0.4 L
Would a salt-cured egg be a physical or chemical change?
For a science experiment, I placed an egg in water that had three tablespoons of salt for one week. After 4 days, the egg cracked. At the end of the week, I took it out and cracked the egg. The egg yolk was now solid. This is also called salt-cured eggs. However, I'm not sure whether this is a physical or chemical change.
Answer:
I believe it is a physical change
Explanation:
The telltale sign of a chemical change is the formation of a new substance. They also usually involve the production of energy (heat, light, sound etc.)
Compared to water, metals heat up faster because they have
Answer: the answer would be a lower specific heat.
Explanation:
What is the lengthening of a muscle without damage? And what is the shortening of a muscle?
Answer:
Stretching is the lengthening and contraction is the shortening
Explanation:
Unless it's asking for eccentric as the stretching and concentric as the shortening
Calculate the percent by mass of the solute in an aqueous solution of 27.2 g ethanol in 250 g of total solution.
Answer:
Explanation:
H
Mass percent can be calculated from the mass of solute in grams divided by the mass of solution multiplied by 100. The percent by mass of the solute in aqueous solution of 27.2 g ethanol in 250 g of total solution 10.88 %.
What is mass percentage?Mass percentage is term used to represent the concentration of a solution. Mathematically mass percent of a component in a mixture is the mass of the component divided by the total mass multiplied by 100.
A solution is made of a solvent and solute. Thus, the total mass of the solution is the sum of mass of solute and mass of the solvent. Here, the solute is ethanol with a mass of 27.2 g. The total mass of solution is 250g.Hence, the mass percent of ethanol can be calculated as follows:
Mass percent of ethanol = mass of ethanol/total mass ×100
= (27.2/250)×100
= 10.88 %.
Hence, the percent by mass of solute ethanol in the total solution is 10.88%.
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Which of the following environments is most likely to have days with a relative humidity of less than 10% (ten percent)?
a desert
a swamp
a rainforest
a deciduous forest
Answer:
Desert
Explanation:
Desert barely have any water therefore they can barely produce any amount of humidity
gases are really _______ and molecules are full of _______, bouncing around constantly
Answer:Gases are really spread out and the atoms and molecules are full of energy - , bouncing around constantly.
Explanation:
What are the final units when you have a mass (in grams), and then divide it by molar
mass
Answer:
The final units are mol
Explanation:
The units of molar mass are grams per mole, g/mol.
This means that when dividing mass by molar mass, the units of grams cancel each other, leaving only units of moles:
Grams ÷ Grams/molAnother way of writing that might help is as follows:
[tex]\frac{g}{\frac{g}{mol}}[/tex]Thus, the final units are moles.
what is the mass of 3.2 moles of NaCl??
Answer:
116.88554 grams
Explanation:
*sweating profusely*
i had to look it up
Answer:
187.01686400000003 grams
Explanation:
someone please answer this question i will mark you brainliest!!
How many particles of ZnCrO4 are present in a 4.5 mole sample?
2.7 × 10²⁴ particles ZnCrO₄
General Formulas and Concepts:Chemistry
Atomic Structure
MolesAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
[Given] 4.5 mol ZnCrO₄
[Solve] particles ZnCrO₄
Step 2: Identify Conversions
Avogadro's Number
Step 3: Convert
[DA] Set up: [tex]\displaystyle 4.5 \ mol \ ZnCrO_4(\frac{6.022 \cdot 10^{23} \ particles \ ZnCrO_4}{1 \ mol \ ZnCrO_4})[/tex][DA] Multiply [Cancel out units]: [tex]\displaystyle 2.7099 \cdot 10^{24} \ particles \ ZnCrO_4[/tex]Step 4: Check
Follow sig fig rules and round. We are given 2 sig figs.
2.7099 × 10²⁴ particles ZnCrO₄ ≈ 2.7 × 10²⁴ particles ZnCrO₄
Use this picture to explain that an electrically charged object can attract an uncharged object without any contact. Your answer should be at least three sentences long. (2 points) a balloon hanging from a string with small pieces of paper stuck to the bottom of it, with a few pieces on the ground
Answer: Insufficient amount of work provided.
Explanation:
I am doing a exam in science need help.
What type of energy comes from the motion of tiny particles of matter?
Answer:
here you are
Explanation:
atomic energy
In order for a roller coaster to work, why does the hill the cart climbs need to be higher than the top of the loop?
Answer:
Explanation:
At the highest point of the first and tallest slope, your potential energy is at its most elevated it will at any point be on this ride. As you plunge, your potential energy diminishes until it's totally gone at the lower part of the slope." The more limited the slope the exciting ride climbs, the more prominent its active energy.
Another way of saying is that
A roller ride works utilizing gravity. the underlying slope must be sufficiently high that gravity can create sufficient force to finish the course.
Brainliest?
7. Define the following terms.
a) Stereoselectivity
b) stereospecific
Explanation:
a) Stereoselectivity = The condition of being stereoselective or a measure of the extent to which a reaction is stereoselective is stereoselectivity.
b) stereospecific = The property of a chemical reaction that yields specific stereoisomers as products.
Calculate the percent composition of C in carbon dioxide.
Answer:
27.27%
Explanation:
Interpret the following equation for a chemical reaction using the coefficients given:
H2(g) + Cl2(g)-------- 2HCl(g)
On the particulate level:
______ of H2(g) reacts with _______ of Cl2(g) to form two molecules of HCl(g).
On the molar level:
______of H2(g) reacts with _______of Cl2(g) to form two moles of HCl(g).
Answer: 1 molecule of [tex]H_2[/tex] reacts with 1 molecule of [tex]Cl_2[/tex] to give 2 molecules of HCl.
1 mole of [tex]H_2[/tex] reacts with 1 mole of [tex]Cl_2[/tex] to give 2 moles of HCl.
Explanation:
The given balanced reaction is:
[tex]H_2(g)+Cl_2(g)\rightarrow 2HCl(g)[/tex]
On the particulate level :
1 molecule of [tex]H_2[/tex] reacts with 1 molecule of [tex]Cl_2[/tex] to give 2 molecules of HCl.
On molar level:
1 mole of [tex]H_2[/tex] reacts with 1 mole of [tex]Cl_2[/tex] to give 2 moles of HCl.
what is heat of reaction
Answer:
Explanation:
The heat of reaction is the energy that is released or absorbed when chemicals are transformed in a chemical reaction. ... The heat of reaction or reaction enthalpy is typically expressed as molar enthalpy in kJ/mol or as specific enthalpy in kJ/kg or kJ/L.
Answer:
The heat of reaction is the energy that is released or absorbed when chemicals are transformed in a chemical reaction. ... The heat of reaction or reaction enthalpy is typically expressed as molar enthalpy in kJ/mol or as specific enthalpy in kJ/kg or kJ/L.
Explanation:
A reaction vessel for synthesizing ammonia by reacting nitrogen and hydrogen is charged with 5.54 kg of H2 and excess N2. A total of 25.6 kg of NH3 are produced. What is the percent yield of the reaction?
Answer:
81.5
Explanation:
smartworks
Marked out of 1.50
A student weights his unknown sample on
uncalibrated balance and obtains a weight of
1.0555 g. If the true weight of the unknown sample
is 1.0755 g, what is the % relative error in his
weight measurements?
+0.94٪
- 1.86%
+1.86%
-0.94
Answer:
+.0.94%
Explanation:
Relative and average atomic mass both describe properties of an element related to its different isotopes. Out of these two Relative atomic mas is more accurate. Thus the % relative error in his weight measurements is +.0.94%.
What is mass?Mass defines the quantity of a substance. It is measured in gram or kilogram. Average mass is the mass of atoms of an element that are isotopes. It can be calculated by multiplying mass of a isotope to natural abundance of that isotope.
The relative mass is the mass that is with respect to mass of a matter that is considered as standard. In chemistry relative mass is equal to the mass of one-twelfth the mass of C-12 isotope .
% relative error=(Difference in weight÷ original weight)×100
Difference in weight= original weight -calculated weight
original weight=1.0755 g
calculated weight=1.0555 g
Difference in weight= 1.0755 g-1.0555 g=0.02g
% relative error=(0.02g÷ 1.0755 g)×100
=+.0.94%
Thus the % relative error in his weight measurements is +.0.94%.
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.50 ml of a solution are diluted to a volume of 100 ml. The concentration of the diluted
solution is 2 M. What was the concentration of the original solution?
pls answer asap! will mark as brainly ist!!
Answer:
4 M
Explanation:
To answer this problem we can use the following formula:
V₁C₁ = V₂C₂Where the subscript 1 refers to the volume and concentration before diluting, and 2 refers to volume and concentration after diluting.
Meaning that in this case we can write:
50 mL * C₁ = 100 mL * 2 MWe can now solve for C₁:
C₁ = 4 M