Answer:
$18.30
Explanation:
The change is the amount left over after the selling price has been matched by the buyer.
Let us find the total cost of what of Ms. Kuhn bought;
For the shirt;
Cost = 4 shirts for $15.95 each = 4(15.95) = $63.8
2 new belts for $8.95 each = 2(8.95) = $17.9
Total cost = $63.8 + $17.9 = $81.7
The amount of change left = $100 - $81.7 = $18.3
3. What determines the frequency (color) of photons?
In the Energy and Specific Heat lab, what temperature should be recorded as the final temperature of the water when measuring the food sample?
A. The temperature of the water when the food sample is first lit
B. The temperature of the water when the food sample has finished burning completely.
C. The highest temperature the water reaches as the sample burns
D. The temperature of the water after the food sample ash has been removed
Answer:
B. The temperature of the water when the food sample has finished burning completely.
Explanation:
Heat or thermal energy is a form of energy that transfers from one object to another due to a temperature difference between the objects. The units for heat are joules or calories.
Calorimetry is the measurement of heat energy released or absorbed in a chemical reaction. A calorimeter is used in calorimetry. The calorimeter operates on the Law of Conservation of Energy which states that energy is never created or destroyed but is transformed from one form to another or between objects.
In food calorimetry, the energy released when food is burned is measured by recording the rise in temperature of water in a calorimeter when a given mass of a food sample is burned completely.
Energy can be calculated using the formula: Q = mc ∆T
where Q = the energy in joules or calories, m = the mass in grams, c = specific heat and ∆T = the change in temperature (final temperature - initial temperature).
The temperature of the water when the food sample has finished burning completely is taken as the final temperature of the water. The sample is allowed to smolder for sometime before recording the final water temperature. This is because the water temperature will continue to rise after the flame has gone out.
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6. What is the mass, in grams, of 1.92 moles of Ca(OH),?
Answer:
Mass = 142.25 g
Explanation:
Given data:
Mass of Ca(OH)₂ = ?
Number of moles of Ca(OH)₂ = 1.92 mol
Solution:
Formula:
Mass = number of moles × molar mass
Molar mass of Ca(OH)₂ = 74.09 g/mol
by putting values,
Mass = 1.92 mol × 74.09 g/mol
Mass = 142.25 g
If you have 3.5 L of He to blow up balloons... at STP...
a) How many moles of He do you have?
b) How many grams of He do you have?
Answer:
B
Explanation:
Calculate the mass of butane needed to produce 99.0 g of carbon dioxide.
Express your answer to three significant figures and include the appropriate units.
Answer:
32.7 g
Explanation:
Step 1: Write the balanced combustion reaction
C₄H₁₀ + 6.5 O₂ ⇒ 4 CO₂ + 5 H₂O
Step 2: Calculate the moles corresponding to 99.0 g of CO₂
The molar mass of CO₂ is 44.01 g/mol.
99.0 g × 1 mol/44.01 g = 2.25 mol
Step 3: Calculate the moles of C₄H₁₀ needed to produce 2.25 moles of CO₂
The molar ratio of C₄H₁₀ to CO₂ is 1:4. The moles of C₄H₁₀ needed are 1/4 × 2.25 mol = 0.563 mol.
Step 4: Calculate the mass corresponding to 0.563 moles of C₄H₁₀
The molar mass of C₄H₁₀ is 58.12 g/mol.
0.563 mol × 58.12 g/mol = 32.7 g
Atom 1 has 19 electrons 19 protons and 20 neutrons atoms 2 has 19 electrons , 20 neutrons and 19 protons
Answer:
Atom 1: Potassium (K)
Atom 2: Same thing
Explanation:
Potassium has an atomic number of 19 and mass number of 39.0983.
Identify the Sun activity that travels from one sunspot to another sunspot.
Group of answer choices
Prominence
corona mass ejection
solar wind
solar flare
Answer:
solar flair I think I'm not sure
What is the oxidation number of calcium
Answer:
0 for the elemental form, +2 in its compounds.
Which statement about Niels Bohr's atomic model is true?
O Higher orbits have lower energies.
O Each orbit has a specific energy level.
O Electrons can exist in any energy level.
O Orbits close to the nucleus have no energy.
Answer:
O Each orbit has a specific energy level.
Explanation:
Neils Bohr put forward his own model of the atom based on the quantum mechanics originally developed by Planck.
He assumed the Rutherford's model and suggested that the extranuclear part consists of electrons in specific spherical orbits around the nucleus.
The orbits/energy level are the permissible through which the electrons can move through.
His concept is based the concept that the electron can move round the nucleus in certain permissible orbitss
helpppp nowwww plssss!!!
Answer: B
Explanation:
How many moles of hydrogen react with 4.5 moles of oxygen to synthesize water?
Answer:
9moles of hydrogen gas
Explanation:
To solve this problem, we write the reaction expression first;
2H₂ + O₂ → 2H₂O
We have been given the number of moles of oxygen gas to be:
Number of moles of oxygen gas = 4.5moles
From the balanced reaction expression:
1 mole of oxygen gas reacts with 2 moles of hydrogen gas
4.5moles of oxygen gas will react with 4.5 x 2 = 9moles of hydrogen gas
Suppose two students grab an end of a rope. Both shake a rope once in a upward direction to create crests traveling at each other. What would you see when crests meet? What type of interference does this show?
Answer:
This creates destructive interference.
Explanation:
When the two ends meet they will cancel each other out.
Both students are shaking the rope in the upward direction. Hence their crest will meet up and form the constructive interference pattern. The intensity of the increases.
What is constructive interference ?When two waves moves in phase, their crest or troughs add up and the amplitude of the wave increases. This phenomenon is called constructive interference.
If the two waves are passing out of phase to each other then they undergo destructive interference. The amplitude of the destructive interference pattern reduces from their initial values.
Here, both students are shaking the rope in the upward direction. Thus, they are in moving in phase. Hence their crest will meet up and form the constructive interference pattern. The intensity of the increases.
Find more on interference?
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PLZ HELP I WILL GIVE BRAINLISTS TO RIGHT ANSWER
2KCIO3 → 2KCI+ 302
How many moles of oxygen are produced by the decomposition of 5.0 moles of potassium chlorate?
A )7.5 mol O2
B )5.0 mol O2
C )2.5 mol O2
D )9.0 mol O2
Which of the following BEST describes how these elements would be classified?
A.
Element Q is a nonmetal and element R is a nonmetal.
B.
Element Q is a metal and element R is a metalloid.
C.
Element Q is a nonmetal and element R is a noble gas.
D.
Element Q is a metal and element R is a noble gas.
Find the Protons and Electrons for nitrogen -3 ion with 7 neutrons.
Answer:
protons: 7; electrons: 10
Explanation:
nitrogen atomic number=# of protons = 7 (doesn't change either in ion or in neutral)
# of electron in neutral N=7
N-3= three electrons are added, thus 7+3=10
Classify each as acidic or basic - pH 9 - pH 2.3 - pH 11 - pH 5 - solution where the concentration of hydronium ions [H ] is 0.0056 M - solution where the concentration of hydronium ions [H ] is 3.45 E-9 M.
Answer:
pH = 9: Basic; pH = 2.3: acidic; pH = 11: basic; pH = 5: Acidic; [H⁺] = 0.0056M: Acidic; [H⁺] = 3.45E-9M: Basic
Explanation:
A solution is defined as acidic when pH < 7 and as basic when pH > 7.
Also, pH = -log[H⁺].
Thus:
pH = 9: >7 → Basic
pH = 2.3: <7 → Acidic
pH = 11: >7 → Basic
pH = 5: <7 → Acidic
[H⁺] = 0.0056M, pH = -log0.0056M = 2.25: <7: Acidic
[H⁺] = 3.45E-9M, pH = 8.46: > 7: Basic
Aniline, consists of carbon, hydrogen, and nitrogen. Combustion of this yields CO2, H20, and N2 as products. If the combustion of 12.5 g of aniline yields 7.1 grams of H2O, and 1.48 grams of N2, what is its empirical formula? [HINT: write out a chemical equation, consider law of conservation of mass, and then think about what percent hydrogen is in water]
A. CHN
B. C2H4N8
C. C16H15N2
D. C20H15N31
The empirical formula : C. C₁₆H₁₅N₂
Further explanationGiven
12.5 g of aniline
7.1 grams of H2O
1.48 grams of N2
Required
The empirical formula
Solution
Reaction :
mass H in H₂O :
= 2.1/18 x 7.1 g
= 0.79
mass N = 1.48
mass C :
= 12.5 g-(mass H+mass N)
= 12.5 - (0.79+1.48)
= 10.23
Mol ratio C : H : N =
= 10.23/12 : 0.79/1 : 1.48/14
= 0.853 : 0.79 : 0.106
= 8 : 7.5 : 1
= 16 : 15 : 2
If the flour mixture is then taken and put into the oven for about 20 minutes, it turns into something very tasty. What kind of change has happened now?
Answer:
physical change
Explanation:
i got the same question sorry for the late response but that's the answer good luck
A catalyst decreases the activation energy of a particular exothermic reaction by 56 kJ/mol, to 35 kJ/mol. Assuming that the mechanism has only one step, and that the products are 78 kJ lower in energy than the reactants, sketch approximate energy-level diagrams for the catalyzed and uncatalyzed reactions. What is the activation energy for the uncatalyzed reverse reaction
Answer:
Activation energy for the uncatalyzed reverse reaction = 103 kJ/mol
Explanation:
Activation energy decreases from = 56 kj/mol to 35 kj/mol
products = 78 KJ lower in energy than reactants
Activation energy for the uncatalyzed reverse reaction = 103 kJ/mol
attached below are the sketches of approximate energy-level for both catalyzed and uncatalyzed reactions
a pressure of 10Nm -2 is equal to ?
Answer:
a pressure of 10 Nm -2 is equal to ?
1 atmosphere
Explanation:
A pressure of 10 N/m² is equal to 10 Pa and 9.86x10⁻⁵ atm.
Pressure (P) is the measure of the perpendicular force (F) applied to an object's surface area (A):
[tex] P = \frac{F}{A} [/tex]
Hence, the unit of the pressure is Newton per square meter (N/m²), which is defined as Pascal (Pa).
[tex] 1 Pa = 1 N/m^{2} [/tex]
Also, we have that 1 atm is equal to 101325 Pa, so:
[tex] P = 1 Pa*\frac{1 atm}{101325 Pa} =9.86 \cdot 10^{-6} atm [/tex]
So, in a pressure of 10 N/m² we have:
[tex] P = 10 N/m^{2} = 10 Pa = 9.86 \cdot 10^{-5} atm [/tex]
Therefore, a pressure of 10 N/m² is equal to 10 Pa and 9.86x10⁻⁵ atm.
You can find more about pressure here: https://brainly.com/question/8033367?referrer=searchResults
I hope it helps you!
PLZ HELP ASAP WILL GIVE BRAINLIST
2AlCl3 + 2Al + 3Cl2
If 20.0 g of aluminum chloride are decomposed, how many molecules of chlorine gas are produced?
A )6.63 x 1022 molecules CI
B )2.70 x 1023 molecules Cl2
C )1.35 x 1023 molecules Cl2
D )9.42 x 1023 molecules Cl2
Explanation:
Molar mass of AlCl3 = 133.34g/mol
Moles of AlCl3 used
= 20.0g / (133.34g/mol) = 0.150mol
Mole Ratio of AlCl3 to Cl2 = 2 : 3,
Moles of Cl2 produced
= 0.150mol * (3/2) = 0.225mol
We know that 1 mole of any gas has
6.023 * 10²³ molecules.
Hence, number of molecules in Cl2
= 0.225mol * (6.023 * 10²³/mol)
= 1.35 * 10²³ molecules. (C)
WORTH 40 POINTS HELLPPPP
What class of element is Astatine (At)?
Answer:
halogen.
nonmetal.
Explanation:
How many cells are a result of Meiosis?
Answer:
2
Explanation:
Cells divide and reproduce in two ways, mitosis and meiosis. Mitosis results in two identical daughter cells, whereas meiosis results in four sex cells.
BALANCE THIS CHEMICAL EQUATION PLS, help:)
Answer:
4C₈H₄OH + 35O₂ → 32CO₂ + 10H₂O
Explanation:
The unbalanced reaction expression is given as:
C₈H₄OH + O₂ → CO₂ + H₂O
To solve this problem, we use a mathematical approach.
aC₈H₄OH + bO₂ → cCO₂ + dH₂O
Conserving C: 8a = c
H: 5a = 2d
O: a + 2b = 2c + d
Let a = 1, c = 8, d = [tex]\frac{5}{2}[/tex] , b = 35
4C₈H₄OH + 35O₂ → 32CO₂ + 10H₂O
what are some sources of error associated with electroplating
Answer:
Cold Shuts. Cold shuts are one of the most common defects found in materials sent for electroplating.
Pitting
Sharp Edges
Cleavage Points
Unclean Manufacturing
Loss of Adhesion
Cracking After Plating — Hydrogen Cracking
Dull and Hazy Deposits in Plating.
Explanation:
What is the mass of 1.75 moles of Ca(H2C302)2?
Explanation:
first we have to find molar mass of ca(H2c3o2)2
40+(1*2)2+(12*3)2+(16*2)2
40+4+72+64=180g/mole
m=n*Mm
m=1.75mole*180g/mole
m=315g
What role do wolves play in the tundra?
Answer:
predator
Explanation:
Wolves, arctic foxes, and snowy owls are predators in the tundra.
Where and in what features is water found on Earth?
Answer: On Earth, liquid water exists on the surface in the form of oceans, lakes and rivers. It also exists below ground as groundwater, in wells and aquifers. Water vapor is most visible as clouds and fog. The frozen part of Earth's hydrosphere is made of ice: glaciers, ice caps and icebergs.
Identify the best practices when storing and using drying agents in the lab.
A. Close the drying agent container whenever it is not in active use.
B. Let the drying agent air out before removing it from the container.
C. Wrap the lid of the drying agent container with tape for storage.
D. Only use drying agent that appears clumpy in its original container.
Answer:
A. Close the drying agent container whenever it is not in active use.
C. Wrap the lid of the drying agent container with tape for storage.
Explanation:
Drying agents also known as desiccants are used in pharmaceutical, food and other manufacturing to keep substances dry. These drying agents are anhydrous and hygroscopic. The right usage of these products requires that they are always stored in an air-tight container.
When they are to be removed from a container containing a solvent, they are to be separated by filtration or decanting.
which of the following describes all of the types of water found in the hydrosphere
Answer: all of the water on the Earth
Explanation:
The hydrosphere is made up of all the water that we have on Earth. Included in the hydrosphere are the water that we have underground, those in the Earth's surface, and those that we have in the air.
On Earth, we can find water in the seas, lakes, oceans, streams, rivers etc. Water also comes in form of rain as well.
