Answer:
a) HCN and NaCN
Explanation:
Buffer solution is made by mixing either a weak base and its salt like ammonia and ammonium chloride or weak acid and its salt like HCN and its salt NaCN or acetic acid and sodium acetate .
In the given option , all of the rest of option has either strong acid or strong base or both . In the last option both are salt so it can not form buffer solution .
It is capable of keeping the pH of the solution constant .
what do you understand by physical change ? give example
Answer:
Physical change are the temporary reversible change in which no new substance is formed.
Example: boiling of milk, melting of wax, cooling water,etc.
You push on the side of a toy truck rolling along the floor. What will happen to the motion of the truck?
Answer:
The direction will be changed .
Explanation:
According to the principles of motion, if an object is moving with solitary velocity and if an external force is applied to it, then that force changes the position, speed, and direction of that object.
In the given question, an external force is being applied to the toy which will change the direction of that toy.
Which of these statements correctly compares probeware (such as an electronic temperature probe) to traditional analog tools (such as a liquid-based thermometer)? Measurements by traditional analog tools are good to a larger number of significant figures. Measurements by traditional analog tools are less prone to experimental error. Probeware is typically very difficult to transport. Probeware is useful for obtaining many measurements in rapid succession.
The correct answer is D. Probeware is useful for obtaining many measurements in rapid succession.
Explanation:
Probeware refers to specialized equipment and programs that collect and analyze data. Indeed, Probeware integrates tools to register information such as distance or temperature with software. This complex system is useful to record and analyze a lot of data or measurements, which is not possible with analog tools. Moreover, due to the integration of software, multiple measurements can be recorded and analyzed in a short time, which is known as rapid succession. According to this, one difference between Probeware and analog tools is that "Probeware is useful for obtaining many measurements in rapid succession."
Answer:
Probeware is useful for obtaining many measurements in rapid succession.
Consider a 0.5 L buffer that contains 0.12 M HOCl and 0.080 M KOCl. What is the pH of this buffer after adding 2.5 mL of 10M KOH to the solution
Answer:
pH = 7.73
Explanation:
The pKa of the HOCl/KOCl buffer is 7.46. To determine the pH of this buffer we can use H-H equation:
pH = pKa + log [A⁻] / [HA]
pH = 7.46 + log [KOCl] / [HOCl]
Where [] is molarity -or moles- of each compound
Initial moles of HClO and NaClO:
HOCl: 0.500L * (0.12mol / L) = 0.06 moles HOCl
KOCl: 0.500L * (0.080mol / L) = 0.04 moles KOCl
Now, HOCl reacts with KOH producing KOCl:
HOCl + KOH → KOCl + H₂O
The moles of KOH in the reaction are:
2.5x10⁻³L * (10mol /L) = 0.025 moles KOH
That means after the reaction, 0.025 moles of HOCl are consumed and 0.025 moles of KOCl are produced.
And after the reaction, moles are:
Final moles:
HOCl: 0.06mol - 0.025mol = 0.035 mol
KOCl: 0.04mol + 0.025mol = 0.065 mol
Replaing in H-H equation:
pH = 7.46 + log [0.065mol] / [0.035mol]
pH = 7.730.000657
significant figures
Answer:
3 Significant Figures
Explanation:
the significant figures in 0.000657 are 6, 5, and 7.
What does this ruler read as ? I need some help !!
Answer: 41 7/10
Explanation: The mark is on the seventh out of ten marks
Which of the following molecules can serve as both a hydrogen bond donor and acceptor? (Select all that apply.) a) CH30PO32. b) (CH3CH2)20 c) NH, CONHd) CH30H e) NH3
Answer:
NH3
Explanation:
A hydrogen bond donor is the supplier of the hydrogen atom that is involved in the hydrogen bonding interaction.
A hydrogen bond acceptor is the electronegative atom that 'accepts' the hydrogen in the hydrogen bond. Such electronegative atoms usually possess an unshared pair of electrons such as nitrogen.
We can see from the above definitions that NH3 is able to act in the capacity of a hydrogen bond donor(due to the presence of three N-H bonds) or as a hydrogen bond donor due to presence of an unshared pair on nitrogen atom.
In a certain chemical process, water reacts with a compound, and the water is converted into another compound during the reaction. Which type of reaction is this?
Answer:
hydration reaction
Explanation:
The type of reaction would be hydration reaction.
Hydration reaction generally involves a chemical reaction of water with another reactant and in which the water ends up being converted to another product entirely.
A good example of hydration reaction is the reaction between alkene and water leading to the production of alcohol.
[tex]CH_2=CH_2(g) + H_2O(g)[/tex] ⇄ [tex]CH_3CH_2OH(g)[/tex]
Answer:
the answer would be hydrolysis, as found on the test and verified by google experts.
How many dm³ of hydrogen,measured at s.t.p.,would be needed to reduce 47.7g of copper(II) oxide to copper?
A. 4.48
B. 6.72
C. 10.82
D. 13.44
help a friend please....will mark brainliest
Answer:
13.44 dm³ of hydrogen is needed for the reaction.
(D) is correct option
Explanation:
Given that,
Mass of copper(II) oxide = 47.7 g
We know that,
Molar mass of CuO = 63.5 + 16 = 79.5 g/mol
We need to calculate the number of moles in 47.7g of copper(II) oxide,
Using formula of moles
[tex]mole=\dfrac{mass}{molar\ mass}[/tex]
Put the value into the formula
[tex]moles=\dfrac{47.7}{79.5}[/tex]
[tex]moles=0.6\ mole[/tex]
Now, we write the balanced equation for the reaction
[tex]CuO+H_{2}\Rightarrow Cu+H_{2}O[/tex]
Here, one mole of CuO reacted with one mole of hydrogen to produce one mole of Cu and one mole of water.
We need to calculate the number of moles of hydrogen needed to react with 0.6 mole of copper(II) oxide
Using the balanced equation,
1 mole of CuO reacted with 1 mole of Hydrogen.
Therefore, 0.6 mole of CuO will also react with 0.6 mole of hydrogen.
We need to calculate the volume of occupied by 0.6 mole of H2 at STP
Using formula of volume
[tex]n=\dfrac{V}{V'}[/tex]
Where, n = mole of hydrogen
V = occupied volume
V'= volume at STP
Put the value into the formula
[tex]0.6=\dfrac{V}{22.4}[/tex]
[tex]V=0.6\times22.4[/tex]
[tex]V=13.44\ dm^3[/tex]
Hence, 13.44 dm³ of hydrogen is needed for the reaction.
what word or two-word phrase best describes the shape of the phosphorus trifluoride ( pf3 ) molecule
Answer:
trigonal pyramidal
Explanation:
There are two characteristics of molecules, one is geometry and other is shape. Shape is excluding lone pair surrounding the central element and geometry is including the lone pair. Therefore, the word or two-word phrase best describes the shape of the phosphorus trifluoride ( PF[tex]_3[/tex]) molecule is trigonal pyramidal.
What is VSEPR theory?
VSEPR stands for valence shell electron pair repulsions. VSEPR theory is used to predict the shape and geometry of molecules on the basis of valence electrons pairs that are present around the central element of the molecule.
According to VSEPR theory, Lone pair lone pair repulsion is greater than bond pair bond pair repulsion. There are so many limitations of VSEPR theory. There is a repulsion between bond pair electrons and lone pairs present on the central element. The word or two-word phrase best describes the shape of the phosphorus trifluoride ( PF[tex]_3[/tex]) molecule is trigonal pyramidal.
Therefore, the word or two-word phrase best describes the shape of the phosphorus trifluoride ( PF[tex]_3[/tex]) molecule is trigonal pyramidal.
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Hypothesis is a educated quess
True
False
Answer:
True
Explanation:
A hypothesis is an educated guess about the outcome of an experiment or thought
Spongebob was trying to make Krabby Patties that weighed 12oz. He made 4 Krabby Patties. They all had the following weights: 12.12oz; 11.9oz; 12.2oz; 12.1oz. Is this an example of Accuracy? Precision? Both? Neither?
Answer:
Yes, the 4 Krabby patties are an example of high precision.
Explanation:
Precision is the closeness of the values obtained by applying them to the same parameter. To calculate the precision, the closeness of each of the values with the mean must be determined, all the values will be taken by subtracting the mean and the values will be taken into account to know which are the most accurate.
(12.12 + 11.9 + 12.2 + 12. 1) / 4 = 12.08
12.12 - 12.8 = 0.04
11.9 - 12.08 = - 0. 18
12.2 - 12.08 = 0.12
12.1 - 12.08 = 0.02
The most accurate precision is that of the fourth Krabby Pattie and the least precise is that of the second.
Explanation:
Step 1: Determine what precision and accuracy is
According to online, "precision is how close measure values are to each other, basically how many decimal places are at the end of a given measurement. Precision does matter. Accuracy is how close a measure value is to the true value. Accuracy matters too, but it's best when measurements are both precise and accurate."
Step 2: Determine which are displayed in this problem
We can see that most of these weight are really close to the original weight which means that the accuracy is pretty high. This means that our weights are fairly close to the original predicated amount.
We can also see that our precision is somewhat decent because most of the numbers bunch up around each other. Precision and accuracy don't have to occur at the same time. For example, a precise collection can be 15, 15.01, 14.99. Although they are far away from the original point, they are bunched up together giving a high precision.
A metal object has a mass of 8.37 g. When it was placed in a graduated cylinder containing 20.0 mL of water, the water level rose to 23.1 mL. What is the density and identity of the metal?
Answer:
Explanation:
mass = 8.37 grams
volume = 23.1 - 20.0 = 3.1 mL
density = mass / volume
density = 8.37 / 3.10 = 2.70
Be sure and add the 0 in your answer. You have 3 places of significant digits.
Which ink spot had the most pigments? Question 3 options: black red blue green Which solvent caused the ink from the dots to move the most? Question 4 options: half water, half alcohol alcohol vegetable oil water
Answer:
The water/alcohol solvent caused the dots to move the most. The oil solvent
Explanation:
6) Select an element from the periodic table that interests you. Look it up on the internet and write down some
interesting facts about it. |
Answer:
Copper (cu)
Explanation:Copper (Cu), chemical element, a reddish, extremely ductile metal of Group 11 (Ib) of the periodic table that is an unusually good conductor of electricity and heat. Copper is found in the free metallic state in nature. This native copper was first used (c. 8000 BCE) as a substitute for stone by Neolithic (New Stone Age) humans.
. Metallurgy dawned in Mesopotamia as copper was cast to shape in molds (c. 4000 BCE), was reduced to metal from ores with fire and charcoal, and was intentionally alloyed with tin as bronze
atomic number 29
atomic weight 63.546
melting point 1,083 °C (1,981 °F)
boiling point 2,567 °C (4,653 °F)
density 8.96 at 20 °C (68 °F)
valence 1, 2
electron configuration 2-8-18-1 or (Ar)3d104s1
Copper is one of the most ductile metals, not especially strong or hard. Strength and hardness are appreciably increased by cold-working because of the formation of elongated crystals of the same face-centred cubic structure that is present in the softer annealed copper.
Copper (Cu), chemical element, a reddish, extremely ductile metal of Group 11 (Ib) of the periodic table that is an unusually good conductor of electricity and heat. Copper is found in the free metallic state in nature. This native copper was first used (c. 8000 BCE) as a substitute for stone by Neolithic (New Stone Age) humans. Metallurgy dawned in Mesopotamia as copper was cast to shape in molds (c. 4000 BCE), was reduced to metal from ores with fire and charcoal, and was intentionally alloyed with tin as bronze
atomic number 29
atomic weight 63.546
melting point 1,083 °C (1,981 °F)
boiling point 2,567 °C (4,653 °F)
density 8.96 at 20 °C (68 °F)
valence 1, 2
electron configuration 2-8-18-1 or (Ar)3d104s1
Copper is one of the most ductile metals, not especially strong or hard. Strength and hardness are appreciably increased by cold-working because of the formation of elongated crystals of the same face-centred cubic structure that is present in the softer annealed copper.
Define molecules distinguish between a molecule of an element and a molecule of a
compound.
Answer:
molecules are the groups of atom bonding together , representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
Please show some work For the reaction: NO(g) + 1/2 O2(g) → NO2(g) ΔH°rxn is -114.14 kJ/mol. Calculate ΔH°f of gaseous nitrogen monoxide, given that ΔH°f of NO2(g) is 33.90 kJ/mol. Answers: 181.9 kJ/mol -35.64 kJ/mol 91.04 kJ/mol 148.0 kJ/mol -114.1 kJ/mol
Answer:
148.04 kJ/mol
Explanation:
Let's consider the following thermochemical equation.
NO(g) + 1/2 O₂(g) → NO₂(g) ΔH°rxn = -114.14 kJ/mol
We can find the standard enthalpy of formation (ΔH°f) of NO(g) using the following expression.
ΔH°rxn = 1 mol × ΔH°f(NO₂(g)) - 1 mol × ΔH°f(NO(g)) - 1/2 mol × ΔH°f(O₂(g))
ΔH°f(NO(g)) = 1 mol × ΔH°f(NO₂(g)) - ΔH°rxn - 1/2 mol × ΔH°f(O₂(g)) / 1 mol
ΔH°f(NO(g)) = 1 mol × 33.90 kJ/mol - (-114.14 kJ) - 1/2 mol × 0 kJ/mol / 1 mol
ΔH°f(NO(g)) = 148.04 kJ/mol
Draw the structural formula for 3-ethyl-3-methyl-1-pentyne. Click the "draw structure" button to launch the drawing utility.
Answer:
See attached picture.
Explanation:
Hello,
In this case, for the given name, you can verify the structure on the attached picture, wherein you can see verify the presence of both the ethyl and methyl radicals at the third carbon as well as the triple bond at the first carbon.
Best regards.
Perform the following calculation, 39 / 24.2 . The answer rounded to the correct number of significant figures is which of the following?
Answer:
Hey!
39 / 24.2 = 943.8
Explanation:
943.8 to 2 s.f (best option for rounding)
= 940
ANSWER = 940
HOPE THIS HELPS!
g How many grams of beryllium are needed to produce "11.5" g of hydrogen gas?Be(s) + 2H 2 O(l) → Be(OH) 2 (aq) + H 2 (g)
Answer:
[tex]m_{Be}=51.3gBe[/tex]
Explanation:
Hello,
In this case, with the given chemical reaction:
[tex]Be(s) + 2H_2 O(l) \rightarrow Be(OH)_ 2 (aq) + H _2 (g)[/tex]
We can notice a 1:1 mole ratio between hydrogen gas and beryllium metal, therefore, beryllium requirement is computed as shown below:
[tex]m_{Be}=11.5gH_2*\frac{1molH_2}{2.02gH_2} *\frac{1molBe}{1molH_2} *\frac{9.01gBe}{1molBe}\\ \\m_{Be}=51.3gBe[/tex]
Regards.
How many grams are in 45.2mg?
Answer:
0.0452
Explanation:
Its Grams and milligrams.Just like dividing by ten, except 3 times.
Which makes up an ecosystem?
A. A community of organisms and nonliving factors in their habitats
B. Several species of organisms that are similar in appearance
C. A group of species and the plants that they interact with
D. Multiple populations of animals and the plants in their environment
How many grams of a 14.0% (w/w) sugar solution contain 62.5
of sugar?
Answer:
[tex]m_{solution}=446.4g[/tex]
Explanation:
Hello,
In this case, by-mass percent is computed in terms of the mass of the solute and the mass of the solvent as shown below:
[tex]\% m=\frac{m_{solute}}{m_{solution}} *100\%[/tex]
Thus, solving for the mass of the solution, we obtain:
[tex]\frac{x}{y} m_{solution}=\frac{m_{solute}}{\% m}*100\%\\ \\m_{solution}=\frac{62.5g}{14.0\%}*100\% \\\\m_{solution}=446.4g[/tex]
Regards.
A racecar burns gasoline to power its engine. As the car is racing around a track, what energy is involved in the system? Check all that apply. mechanical energy chemical energy thermal energy electromagnetic energy
Answer:
The internal combustion engine in the car converts the potential chemical energy in gasoline and oxygen into thermal energy which is transformed into the mechanical energy that accelerates the vehicle (increasing its kinetic energy) by causing the pressure and performing the work on the pistons.
Answer:
A, B, and C are the correct options.
Explanation:
I just did it on Edge2023
Can someone explain to me what I'm doing wrong? 68mL was wrong as well. Selecting "tenths place" for 3a and "hundredths place" for 3b and then putting a decimal was wrong as well. I'm lost as to what I should do.
Answer:
Tens place
Ones place
69.5 ml
Explanation:
Hi! Sorry about your frustration.
Looking at the attachment again, I can then say that
3a) the answer would be only tens place. You may think ones place is correct, but then again look at the beaker. Are there any measurement in ones graduated on it? The question says "certain", while it's possible to calculate in ones, you most likely would be guessing and not certain about it.
3b) from the explanation I did in 3a above, it is thus clear ones place is the answer here. Calculating in tens is very certain, calculating in tenth and hundredth place is quite hard, if not impossible. Therefore, ones place is possible, but uncertain.
3c) If both 68 & 69 are incorrect, I'd advise you try something even much closer to 70, in 69.5
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30.0 mL of pure water at 282 K is mixed with 50.0 mL of pure water at 343 K. What is the final temperature of the mixture
The final temperature of the mixture will be "305.6 K".
Heat and temperatureAccording to the question,
Mass of water, m₁ = 30.0 mL or,
= 30.0 mL × 1 g/mL
= 30.0 g
and,
m₂ = 50.0 mL × 1 g/mL
= 50.0 g
Specific heat of water = 4.18 J/g°C
We know the relation,
→ Heat lost + Heat gained = 0
By substituting the values,
30.0 × 4.18 (T - 282) + 50.0 × 4.18 (T - 320) = 0
30.0 × 4.18T - 1178.76 + 50.0 × 4.18T - 1337.6 = 0
hence,
The final temperature will be:
T = 305.6 K
Thus the answer above is appropriate.
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What volume (cm 3 ) would 9.0 grams of aluminum occupy? Density is 2.7 g/cm 3 . Show your work
Answer:
3.3 cm³
Explanation:
Use the density formula, d = m/v, to solve for the volume:
2.7 = 9.0/v
2.7v = 9.0
v = 3.3 cm³
What is the minimum mass of magnetite (Fe,O2), a iron ore, from which 120. g of pure iron could be extracted? Be sure your answer has a unit symbol, if necessary, and is rounded to 3 significant digits.
Answer:
166 g
Explanation:
Step 1: Write the reaction for the obtaining of Fe from magnetite
Fe₃O₄ ⇒ 3 Fe + 2 O₂
Step 2: Calculate the moles corresponding to 120 g of Fe
The molar mass of Fe is 55.85 g/mol.
120 g × (1 mol/55.85 g) = 2.15 mol
Step 3: Calculate the moles of Fe₃O₄ required to produce 2.15 moles of Fe
The molar ratio of Fe₃O₄ to Fe is 1:3. The moles of Fe₃O₄ required are 1/3 × 2.15 mol = 0.717 mol
Step 4: Calculate the mass corresponding to 0.717 moles of Fe₃O₄
The molar mass of Fe₃O₄ is 231.53 g/mol.
0.717 mol × 231.53 g/mol = 166 g
Balance the following oxidation-reduction reaction and indicate which atoms have undergone oxidation and reduction.
____Cu + ____HNO3 ----> ____Cu(NO3)2 + _____NO2 + _____H2O
You should research it on quizlet.
how to calculate average mass in grams?
Explanation:
hope these help you answer