Answer:
the invention of the microscope has made seeing bacteria/cells, examining forensic evidence (such as fingerprints), studying atomic structure, tissue analysis, and the study of our ecosystem possible to the naked eye
Explanation:
hope this helps
Calculate the pH of a solution that is prepared by dissolving 0.23 mol of hydrofluoric acid (HF) and 0.57 mol of hypochlorous acid (HClO) in water and diluting to 3.60 L. Also, calculate the equilibrium concentrations of HF, F2, HClO, and ClO2. (Hint: The pH will be determined by the stronger acid of this pair.)
Answer:
The equilibrium concentrations of HF = 0.058 , F2 = 0.006M , HClO =0.16M , and ClO2 = 7.7 × 10⁻⁷M.
Explanation:
The Ka values for HClO₃ and HF are given as 2.9 × 10⁻⁸ and 6.6 × 10⁻⁴ respectively. The molar concentration for HF = 0.23/ 3.60L = 0.064 M and 0.57/ 3.60 = 0.16 M.
When HF is reacted with water, it ionizes to form H₃O⁺ and F⁻. The concentration of H₃O⁺ and F⁻ can be calculated below:
HF(aq) <------------------------> H30^+ + F^-.
Ka = [H^+] [F^-]/[HF] .
6.6× 10^-4 = [x][x]/ ( 0.064- x).
x = 0.0060 M.
The concentration of H₃O⁺ and F⁻ = 0.0060 M respectively.
The pH = - log [ H₃O⁺ ] = -log [0.0060] = 2.22.
When HClO is reacted with water, it ionizes to form H₃O⁺ and F⁻. The concentration of H₃O⁺ and ClO⁻ can be calculated below:
HClO(aq) <------------------------> H30^+ + ClO^-.
Ka = [H^+] [ClO^-]/[HClO] .
6.6× 10^-4 = [0.006 + x] [x]/ ( 0.16 - x).
x = 7.7 × 10^-7M.
[ClO^-] = 7.7 × 10^-7 M.
[HClO] = 0.16 - 7.7 × 10^-7 = 0.16M.
[F^-] = 0.006 M.
[HF] = 0.064 - 0.006 = 0.058 M.
Help pls!!!!!!!!!!!!!!!!!!!
Answer:
water
Explanation:
water is made up of both hydrogen and oxygen (h2o)
Calculate the number of moles in 15.5g of CaSO4.5H2O
Answer:
No. of moles = 0.0685
Explanation:
Given mass, m = 15.5g
We need to find the number of moles in 15.5 g of CaSO₄.5H2O
First, we find the mass of CaSO₄.5H2O.
M = (1×40)+(1×32)+(4×16)+(5×18)
M = 226 g/mol
We know that,
Number of moles = given mass/molar mass
[tex]n=\dfrac{15.5\ g}{226\ g/mol}\\\\n=0.0685\ \text{mol}[/tex]
Hence, there are 0.0685 moles in 15.5 g of CaSO₄.5H2O.
How does the appearance of a substance change when it
changes phase?
Answer:
Melting: the substance changes back from the solid to the liquid. Condensation: the substance changes from a gas to a liquid. Vaporization: the substance changes from a liquid to a gas. Sublimation: the substance changes directly from a solid to a gas without going through the liquid phase.
Explanation:
The change in appearance of a substance when it changes its phase includes :
Change in volume Change in texture and Change in shapeChange in volume : when a liquid substance is heated to its boiling point ( vaporization) the volume of the liquid substance will change when it turns into gas because gases have no definite volume or shape.
Change in Texture: When water freezes it changes its state from a liquid state to a solid state, also the appearance of the liquid water will undergo changes in its texture when it is in its' solid state ( i.e. the texture of ice is not exactly the texture of liquid water )
Change in shape : when a solid substance changes its state from solid to gas ( sublimation ) the shape of the solid substance will be lost during the phase change.
Hence we can conclude that the change in the appearance of a substance when it changes its phase include. Change in volume, Change in texture and Change in shape.
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What is the answer for number 9 in the Half-life gizmo activity B.
There is a third bromobutene structure that could have been formed in the addition of HBr to butadiene: cis-1-bromor-2-butene (the cis isomer of structure 2). Draw this structure. Would you predict (no calculation) its heat of formation to be more or less negative that the trans isomer? Explain.
Answer:
its less negative hope I helped buster
Because trans isomers are more stable than cis isomers, the cis isomer will have a less negative heat of formation than the trans isomer.
What are cis- and trans- isomers?Cis- and trans isomers are compounds that have different configurations in space because of the presence of a rigid structure or functional groups in their molecule.
Cis atoms have functional groups on the same side.
Trans isomers have functional groups on alternate different.
The structure of cis-1-bromor-2-butene is attached.
Generally, trans isomers are more stable than cis isomers..
Stable compounds have more negative heat of formation while unstable compounds have less negative heat of formation.
Therefore, the cis isomer will have a less negative heat of formation than the trans isomer.
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Density of water calculation using a 10 mL graduated cylinder
10 mL graduated cylinder + 10 mL unknown liquid (g) 10 mL graduated cylinder (g) Volume of liquid (mL) Density (g/mL)
Trial 1 19.731 9.861 10.0
Trial 2 19.831 9.861 10.0
Trial 3 19.831 9.861 10.0
Trial 4 19.771 9.861 10.0
Trial 5 19.751 9.861 10.0
Required:
Calculate the average density for the gradudated cylinder measurements.
Answer:
Average density of the liquid = 0.992 g/mL
Explanation:
Density = mass/volume
mass of liquid = (mass of liquid + mass of cylinder) - mass of cylinder
Trial 1: mass of liquid = 19.731 - 9.861 = 9.87
volume of liquid = 10 mL
density of liquid = 9.87 g / 10 mL = 0.987 g/mL
Trial 2: mass of liquid = 19.831 - 9.861 = 9.97
volume of liquid = 10 mL
density of liquid = 9.97 g / 10 mL = 0.997 g/mL
Trial 3: mass of liquid = 19.831 - 9.861 = 9.97
volume of liquid = 10 mL
density of liquid = 9.97 g / 10 mL = 0.997 g/mL
Trial 4: mass of liquid = 19.771 - 9.861 = 9.91
volume of liquid = 10 mL
density of liquid = 9.91 g / 10 mL = 0.991 g/mL
Trial 5: mass of liquid = 19.751 - 9.861 = 9.89
volume of liquid = 10 mL
density of liquid = 9.89 g / 10 mL = 0.989 g/mL
Average density = (0.987 + 0.997 + 0.997 + 0.991 + 0.989)/5 = 4.961/5
Average density of the liquid = 0.992 g/mL
A solid sample of Zinc Hydroxide is added to 0.350 L of 0.500 M aqueous Hydrogen Bromide. The solution that remains is still acidic. It is then titrated with 0.500 M NaOH solution, and it takes 88.5 mL of the NaOH solution to reach the equivalence point. What mass of Zinc Hydroxide was added to the Hydrogen Bromide solution?
Answer:
6.499 g
Explanation:
One part of the aqueous HBr reacted with Zinc Hydroxide following the reaction:
Zn(OH)₂ + 2HBr → ZnBr₂ + 2H₂OAnd the remaining HBr reacted with NaOH:
NaOH + HBr → NaBr + H₂OFirst we calculate how many HBr moles remained after reacting with Zn(OH)₂. That number equals the number of NaOH moles used in the titration:
0.500 M * 88.5 mL = 44.25 mmol NaOH = mmol HBrNow we calculate how many moles of HBr reacted with Zn(OH)₂:
Originally there were (350 mL * 0.500 M) 175 mmol HBr175 mmol - 44.25 mmol = 130.75 mmol HBrThen we convert those 130.75 mmoles of HBr to the Zn(OH)₂ moles they reacted with:
130.75 mmol HBr * [tex]\frac{1mmolZn(OH)_{2}}{2mmolHBr}[/tex] = 65.375 mmol Zn(OH)₂.Finally we convert Zn(OH)₂ moles to grams:
65.375 mmol Zn(OH)₂ * 99.424 mg/mmol = 6499.8 mg Zn(OH)₂6499.8 mg Zn(OH)₂ / 1000 = 6.499 gWhat important function do currents and areas of upwelling provide for living things
in the sea?
Recycles the ocean water through evaporation and precipitation
Brings nutrients up from deeper water for use by organisms
Mixes land and sea organisms to broaden the food web
Allows Earth to have weather and climate changes
What type of equation is this?
AlCl3 + NaOH → Al(OH)3 + NaCL
double
single
synthesis
decomp
combustion
Choose the correct statement regarding the behavior of water.Group of answer choicesThe heat capacity of liquid water is greater than the heat capacity of solid ice.The water phase with the smallest temperature increase when adding 10 kcal of heat is solid ice.Ice has a higher density than liquid water and therefore sinks.The water phase with the smallest temperature increase when adding 10 kcal of heat is gas vapor.The heat capacity of gas vapor is greater than the heat capacity of liquid water.
Answer:
The water phase with the smallest temperature increase when adding 10 kcal of heat is solid ice.
Explanation:
The rest of the statements are incorrect. The density of ice is lower than the density of water. The heat capacity of solid ice is greater almost twice the heat capacity of the liquid water. The heat capacity of vapors is less than heat capacity of liquid.
The picture has my question
Answer:
b or c
Explanation:
a reaction vessel contains a small piece of magnesium metal and air (20%) of which is oxygen gas. The mixture is ignited and burns with a burst of light and heat, producing solid magneisum oxide. The mass of mgO, however, is less than the initital mass of magnesium and oxygen combined. What loss of mass
Answer: see below
Explanation:
Mg burning in air gives MgO and a smaller amount of Mg3N2
2Mg+O2=2MgO. 2*24.3+32=2*40.3
3Mg+N2=Mg3N2
Ignoring the nitride, MgO loss of mass during the reaction can be ascribed to
(1) relativistic loss as energy (too small to be measurable)
(2) During the reaction, which is strongly exothermic, a fraction f the material is blown off as tiny particles which adhere to the vessel.
Use the periodic table to select the element that best fits each of the following descriptions.
Noble gas:
O oxygen
O chlorine
Okrypton
Answer:
Krypton
Explanation:
Which orbital is partially filled in the Zirconium (ZI) atom?
Answer:
4d orbital.
Explanation:
Hello!
In this case, since zirconium's atomic number is 40, we fill in the electron configuration up to 40 as shown below:
[tex]1s^2,2s^2,2p^6, 3s^2,3p^6,4s^2,3d^{10},4p^6,5s^2,4d^2[/tex]
Thus, the orbital 4d is partially filled.
Best regards!
The orbit closest to the nucleus has ___________ energy.
Answer:
inonic bonds with cavalent bonds
Explanation:
ionic bonds
35.2 J of heat is
applied to 16.0 g
of a substance.
Temp rises by 7.2
K. Specific Heat?
The specific heat : c = 0.306 J/g K
Further explanationGiven
Heat = 35.2 J
Mass = 16 g
Temperature difference : 7.2 K =
Required
The specific heat
Solution
Heat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
Input the value :
c = Q / m.∆T
c = 35.2 / 16 x 7.2
c = 0.306 J/g K
a certain kind of pea plant has an allele for tall and an allele for short but its overall phenotype is tall.
Answer:
Tt
Explanation:
T= Dominant tall
t= non-dominant short.
Dominant always shows over non-dominant.
Examine the diagram of the cell cycle.
Which label identifies the stage in which the DNA is copied and the cell grows?
A-W
B-X
C-Y
D-Z
Explanation:
i think w is the required answer
Which of these describes the essential conclusion of the Rutherford experiment? The atom contains a very small nucleus that contains most of its mass. The proton is positively charged and the neutron has no charge? Atoms are solid spheres with electrons suspended in them like chocolate chips in a cookie. Mass is neither made nor consumed in a chemical reaction.
Answer:
The atom contains a vey small small nucleus that contains most of its mass.
Explanation:
The Rutherford gold leaf experiment concluded that most (99%) of all the mass of an atom is in the nucleus of the atom, that the nucleus is very small (105 times small than the size of the atom) and that is is positively charged.
If you were to burn a candle inside of a closed jar and the mass of the
closed jar and candle was 50 grams to begin with, what would the mass of
the jar and smoke be after the candle is done burning?
Answer:
50g
Explanation:
At the end of the burning process, the mass of the jar and smoke should be 50g after the candle burning is done.
In most systems, the law of conservation of matter finds expression. According to this law "matter is neither created nor destroyed but atoms are rearranged".
In this kind of system, no matter is allowed to escaped and the starting mass of the reactants compared to that of the product will be the same.
Pls answer this two ASAP PLSSSSSSSS
Answer:
1. aa
2. They have similar DNA
Explanation:
1. According to the question 1, wrinkled seeds (A) are dominant over round seeds (a) in pea plants. This means that, based on the law of dominance proposed by Mendel, wrinkled seeds will be expressed over round seeds in a heterozygous state (Aa).
However, since the round seed phenotype is a recessive trait, it will only be expressed when the alleles for round seeds (a) are the same in the gene i.e. aa genotype.
2. Based on the information in question 2, Ricky, who is working on a family tree for his school project, realizes that his close relatives all look similar in the pictures he collected. This is possible because of the SIMILARITY OF THEIR DNA (genetic material). Note that, relatives are connected by the genes that are inherited from one another, hence, they possess a similar DNA, which is the most valid reason for the resemblance.
Give the formula of the alkanes his molecule contains 28 hydrogen atoms
Answer:
jayfeather friend me
Explanation:
Table 1. Summary of the Straight-Chain Alkanes
Name Formula Number of Structural Isomers
Octadecane C18H38
Nonadecane C19H40
Eicosane C20H42 366,319 (!)
29 more rows
The formula of the alkanes the molecule contains 28 hydrogen atoms is [tex]C_1_3H_2_8[/tex], i.e., tridecane.
What are alkanes?Alkanes are organic compounds made up entirely of single-bonded carbon and hydrogen atoms with no other functional groups.
Alkanes have the general formula CnH2n+2 and are classified into three types: linear straight-chain alkanes, branched alkanes, and cycloalkanes.
Alkanes are important raw materials in the chemical industry and the main component of gasoline and lubricants.
Natural gas is primarily composed of methane and ethane and is used for heating, cooking, and power generation (gas turbines).
Natural gas and petroleum are separated from the alkanes. Natural gas is primarily composed of methane, with trace amounts of other low molecular weight alkanes.
All other alkanes are derived from petroleum, which is a complex mixture of many compounds.
Here, the formula for 28 hydrogen atom containing alkane is
[tex]C_1_3H_2_8[/tex]
Thus, this given formula is of tridecane.
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How many molecules are in 97.21 grams of Sodium Chloride (NaCl)?
Consider a reaction that connects the ends of a chain of carbons to form a ring. The closure of the ring results in the formation of a new chemical bond, with the bonding electrons going into a bonding sigma molecular orbital at a lower energy. Which of the following statements correctly describes the resulting enthalpy, entropy, and heat changes? Mark all that are correct.
A. The entropy of the surroundings decreases (AS surr < 0) because the closure of the ring results in fewer conformations for the system.
B. The system releases energy to the environment, because its internal energy decreases.
C. The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.
D. The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.
E. The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.
Answer:
The system releases energy to the environment, because its internal energy decreases.
The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.
The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.
The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.
Explanation:
Now we know that when a reaction is exothermic heat is given off. In this case, we have a reaction that connects the ends of a chain of carbons to form a ring. The bonding electrons now move into a lower energy bonding sigma molecular orbital.
This leads to a decrease in the entropy and enthalpy of the system because energy is given off, the closure of the ring reduces the number of conformations the ring can adopt and the electrons that form the bond enter an orbital that is at a lower energy.
The entropy of the surroundings is increased as energy is given out. The surroundings absorb heat released by the reaction, and become more disordered.
Pls answer this ASAP thank you
Answer:
The anwer is not D the anwer is A
Explanation:
Help solve please, it’s due in less than an hour or so.
sorry i can only figure out 1 but the answer is
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124
hope you do good on your test :D
what are three things that are considered a chemical change
Answer:
Color change, precipitation, bubbling
Explanation:
Chemical change changes the chemical composition and undergoes a process in which it results as a new substance.
How many atoms are in 0.580 moles of CO2?
Answer:
[tex]1.05x10^{24}atoms[/tex]
Explanation:
Hello!
In this case, according to the definition of the Avogadro's number, it is possible to realize that one molecule of CO2 contains 3 moles of atoms, one of carbon and two of oxygen, thus, we have:
[tex]0.580molCO_2*\frac{3mol\ atoms}{1molCO_2} =1.74mol\ atoms[/tex]
Then, we use the Avogadro's number to obtain:
[tex]1.74mol\ atoms*\frac{6.022x10^{23}atoms}{1mol\ atoms} \\\\1.05x10^{24}atoms[/tex]
Best regards!
ou are a work study for the chemistry department. Your supervisor has just asked you to prepare 500 mL of 3 M HCl for tomorrow’s undergraduate experiment. In the stockroom explorer, you will find a cabinet called "stock solutions". Open this cabinet to find a 2.5 L bottled labeled "11.6 M HCl". The concentration of the HCl is 11.6 M. Please prepare a flask
Answer:
Add to a 500mL volumetric flask 300mL of water, the 129mL of the 11.6M HCl solution and then complete to volume with water
Explanation:
To make 500mL = 0.500L of a 3M HCl from the 11.6M HCl stock we need first to find the moles of HCl we need:
Moles HCl:
0.500L * (3mol / L) = 1.5 moles of HCl are needed
These moles are obtained from the 11.6M HCl solution. The volume required is:
1.5mol * (1L / 11.6moles HCl) = 0.129L = 129mL must be added to the solution.
That means to prepare the 500mL of the 3M HCl you need to:
Add to a 500mL volumetric flask 300mL of water, the 129mL of the 11.6M HCl solution and then complete to volume with water
Answer:
Calculation: 11.6 M × V = 3.0 M × 0.500 liters
V = 0.13 liters
Steps for dilution:
Measure out 0.13 liters of the concentrated solution of 11.6 M HCl using a volumetric pipet.
Transfer this into solution into a 500 milliliter volumetric flask.
Add water to the flask until it reaches a total volume of 500 milliliters.
Solution: V = 0.13 liters
Explanation: