Answer:
False
Explanation:
1. Lani conducted an experiment in which she tested the reactivity of a substance. She placed two
equal samples of a substance into identical beakers. She then filled one beaker with water and
filled the other with vinegar. After a week, she measured the samples. What was the
independent variable in her experiment?
Answer:
the independent variable is the beakers
Explanation:
Is crumbling a cookie, a physical change? Explain why. My child is having problems with this question, and I'm not so sure how to explain it.
Answer:
Because the sugar flour and eggs can no longer be separated. The properties of the materials have changed so it's a chemical change
Sugar, flour, and eggs cannot be separated. The materials' properties have changed, resulting in a chemical change.Therefore, crumbling a cookie is not a physical change.
What is physical change ?Physical changes affect a chemical substance's form but not its chemical composition. Physical changes can be used to separate mixtures into their component compounds, but not to separate compounds into chemical elements or simpler compounds.
A chemical change is the transformation of one material into another, the formation of new materials with different properties, and the formation of one or more new substances. It occurs when one substance reacts with another to form a new substance.
A physical change is characterized by a change in physical properties. Melting, transition to a gas, change in strength, change in durability, changes in crystal form, textural change, shape, size, colour, volume, and density are all examples of physical properties.
Thus, crumbling a cookie is not a physical change.
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One isotope of Carbon(C) has exactly the same mass number and atomic mass since it was used as the definition of the atomic mass unit. Which isotope is it and what is it’s atomic mass?
How many oxygen atoms are there in 450.0 grams of Na2SO4?
Answer:
112.5
Explanation:
I think so because in one unit has 4 oxygen atoms.
The gas cyclobutane, C4H8(g), can be used in welding. When cyclobutane is burned in oxygen, the reaction is: C4H8(g) + 6 O2(g)4 CO2(g) + 4 H2O(g) (a) Using the following data, calculate ΔH° for this reaction. ΔH°f kJ mol-1: C4H8(g) = 27.7 ; CO2(g) = -393.5 ; H2O(g) = -241.8 ΔH° = kJ (b) Calculate the total heat capacity of 4 mol of CO2(g) and 4 mol of H2O(g), using CCO2(g) = 37.1 J K-1 mol-1 and CH2O(g) = 33.6 J K-1 mol-1. C = J K-1 (c) When this reaction is carried out in an open flame, almost all the heat produced in part (a) goes to raise the temperature of the products. Assuming that the reactants are at 25°C, calculate the maximum flame temperature that is attainable in an open flame burning cyclobutane in oxygen. The actual flame temperature would be lower than this because heat is lost to the surroundings. Maximum temperature = °C
Answer:
a
[tex]\Delta H^o _{rxn} = -2568.9 \ kJ [/tex]
b
[tex]H = 350 JK^{-1}[/tex]
c
[tex]T_{max} = 32.4 ^o C[/tex]
Explanation:
From the question we are told that
The reaction of cyclobutane and oxygen is
[tex]C_4H_8_{(g)} + 6 O_2_{(g)} \to 4 CO_2_{(g)} + 4 H_2O_{(g)}[/tex]
ΔH°f (kJ mol-1) : C4H8(g) = 27.7 ; CO2(g) = -393.5 ; H2O(g) = -241.8 ΔH° = kJ
Generally ΔH° for this reaction is mathematically represented as
[tex]\Delta H^o _{rxn} = [[4 * \Delta H^o_f (CO_2_{(g)} ) + 4 * \Delta H^o_f(H_2O_{(g)} ] -[\Delta H^o_f (C_2H_6_{(g)} + 6 * \Delta H^o_f (O_2_{(g)}) ] ][/tex]
=> [tex]\Delta H^o _{rxn} = [[4 * (-393.5) + 4 * (-241.8) ] -[ 27.7 + 6 * 0][/tex]
=> [tex]\Delta H^o _{rxn} = -2568.9 \ kJ [/tex]
Generally the total heat capacity of 4 mol of CO2(g) and 4 mol of H2O(g), using CCO2(g) = 37.1 J K-1 mol-1 and CH2O(g) = 33.6 J K-1 mol-1. C = J K-1 is mathematically represented as
[tex]H = [ 4 * C_{CO_2_{(g)}} + 6* C_{CH_2O_{(g)}}][/tex]
=> [tex]H = [ 4 * 37.1 + 6* 33.6 ][/tex]
=> [tex]H = 350 JK^{-1}[/tex]
From the question the initial temperature of reactant is [tex]T_i = 25^oC[/tex]
Generally the enthalpy change([tex]\Delta H^o _{rxn}[/tex]) of the reaction is mathematically represented as
[tex]|\Delta H^o _{rxn} |= H * (T_{max} -T_i)[/tex]
[tex] 2568.9 = 350 * (T_{max} -25)[/tex]
=> [tex]\frac{2568.9 }{350} = T_{max} - 25[/tex]
=> [tex]T_{max} = 32.4 ^o C[/tex]
The elwments in group 17 of the periodic table are all halogens. All halogens have the same ______.
A. Atomic number
B. Atomic mass
C. Number of possible isotopes
D. number of valence electrons
Group 17 elements called halogens . All halogens have the same number of valence
electrons
Whose measurements are more precise?20.3 cm and 21.0cm
Answer:
will i think the 21.0cm
What does Newton’s first law of motion state?
Answer:
Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This is normally taken as the definition of inertia. ... If that velocity is zero, then the object remains at rest.
Explanation:
Answer:
Before Galileo and Newton, many people thought that objects lost speed because they had a built-in natural tendency to do so. But those people weren't taking into account the multiple forces here on Earth - for example, friction, gravity, and air resistance - that cause objects to change their speed. If we could see the motion of an object in deep interstellar space, we would be able to observe the natural tendencies of an object that is free from any external influence. In deep interstellar space we would observe that if an object had a speed, it would continue to move with that speed until there was some force causing a change in its motion. Likewise, if an object were at rest in interstellar space, it would remain at rest until there was a force causing a change in its motion.
Explanation:
Hope it helped you =)
Explain the purpose of the Parados and summarize the text. In addition, infer how the Parados reveals tone and evokes mood. Finally, analyze how the text reveals the beliefs of the ancient Greek people.
Answer:
The purpose of the Parados is to add an explanation of events that happened before the play begins. In the first section the mood is triumphant because of the recent battle win. Then it jumps back to the beginning of the battle and the mood is scared. Before the army lead by the brother of the king could attack they are forced to retreat and the army counterattacks. Unfortunately, the brothers kill each other during the battle. The people of Ancient Greece believed that Zeus and Ares were on their side and used the gods as the excuse for winning a battle. The story ends victorious but sad tone because the two brothers have slain each other.
Explanation: Gets you 100%
2) 3,160 tons of water flows over Niagra Falls every second. Assuming the water has a density of 1.00 g/ml,
how much time would it take the water to fill up a cylinder with the diameter of a school garbage can (53 cm)
that stretched to the moon, which is on average 236,000 miles from the earth? Answer in a time unit that is
most meaningful (for example 1.40 days is more meaningful than 121,000 seconds). 1 ton = 2000 pounds
Answer:
Time = 8.12 h = 0.34 day
Explanation:
First we find speed of water flow:
Speed = u = (3160 tons/s)(907.185 kg/1 ton)
u = 2866704.6 kg/s
also,
Density = (1 g/mL)(1 mL/1 x 10⁻⁶ m³)(1 x 10⁻³ kg/1 g)
Density = 1000 kg/m³
Now,
Volume Flow Rate = Speed/Density
Volume Flow Rate = (2866704.6 kg/s)/(1000 kg/m³)
Volume Flow Rate = 2866.7 m³/s
Now, we find volume of cylinder:
Volume = (Area)(Length)
Volume = (πd²/4)(L)
Volume = [(π)(0.53 m)²/4][236000 mi][1609.36 m/1 mi]
Volume = 83,792,823.82 m³
Now,
Time = Volume/Volume Flow Rate
Time = (83,792,823.82 m³)/(2866.7 m³/s)
Time = (29299.71 s)(1 h/3600 s)
Time = 8.12 h = 0.34 day
The is the
variable that
gets measured
Answer:
what? what's the full question?
BRAINLIEST!!!!!!!!!!
Lard, Lye, and Salt are combined to make Glycerin (a sweet-tasting substance found in lotion) and Soap. This process makes some left-over material as a waste product. If 30.0 kg of lard, 20.0 kg of lye, and 5.0 kg of salt are combined and 25.0 kg of glycerin and 5.0 kg of waste are produced, what mass of soap is made? Show all work.
Explain how question demonstrates the Law of Conservation of Mass.
Answer:
30
Explanation:
25.0 + 5.0 = 30
Answer:
30
Explanation:
50 mL of 2.2 M HCl is combined with 50 mL of 2.0 M NaOH in a coffee-cup
calorimeter. The temperature of the solution increases 13.4°C. Assume the
calorimeter is a perfect insulator and the mixture has a specific heat capacity identical
to pure water (4.184 wc)
.
Calculate the heat change from the chemical reaction (in units of kJ). (Pay attention to
sign conventions and do not write the units in your typed answer.)
Answer:
-56.1kJ/mol
Explanation:
The reaction between HCl and NaOH is:
NaOH + HCl → NaCl + H₂O + ΔH
Where ΔH is heat change in the reaction.
As the temperature of the solution increases, the heat is released and ΔH < 0
The heat released in the reaction is obtained using coffe-cup calorimeter equation:
Q = C×m×ΔT
Where Q is heat
C is specific heat of the solution (4.184J/g°C)
m is mass of solution: Assuming density = 1g/mL, 100mL of solution = 100g
And ΔT is change in temperature (13.4°C)
Replacing:
Q = C×m×ΔT
Q = -4.184J/g°C×100g×13.4
Q = -5606.6J
Now, in the reaction you have:
Moles HCl:
0.050L * (2.2mol/L) = 0.11 moles
Moles NaOH:
0.050L * (2.0mol/L) = 0.1 moles
That means the moles of reaction are 0.1 moles, and heat change in the chemical reaction is:
5606.6J / 0.1 mol = 56066J =
-56.1kJ/mol
Here is a more complex redox reaction involving the permanganate ion in acidic solution
In the redox reaction involving the permanganate ion in acidic solution, permanganate ion is reduced to manganese (ii) ion while iron (ii) ion is oxidized to iron(iii) ion.
What is a redox reaction?A redox reaction is a reaction in which reduction and oxidation occurs at the same time and to the same extent.
An example of a redox reaction is the reaction involving the permanganate ion and tetraoxosulphate (vi) ion in acidic solution.
The equation of the reaction is given below:
[tex]MnO_{4}^{ - } (aq) + 5Fe^{2+}(aq) + 8H^{+} \rightarrow Mn^{2+}(aq)+ 5Fe^{3+}(aq) +4H_{2}O(l) \\ [/tex]
Therefore, in the redox reaction involving the permanganate ion in acidic solution, permanganate ion is reduced to manganese (ii) ion while iron (ii) ion is oxidized to iron(iii) ion.
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Calculate the volume of a 0.750 M solution containing 67.0 g of KNO3
(gives you 20 points!)
Answer:
Volume of solution is 0.88 L.
Explanation:
Given data:
Molarity of solution = 0.750 M
Mass of KNO₃ = 67.0 g
Volume of solution = ?
Solution:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
Now we will calculate the number of moles.
Number of moles = mass/molar mass
Number of moles = 67.0 g/ 101.1 g/mol
Number of moles = 0.66 mol
Now we will put the values in molarity formula.
0.750 M = 0.66 mol / L of solution
L of solution = 0.66 mol / 0.750 M
L of solution = 0.88 L
Volume of solution is 0.88 L.
PLZ ANSWER QUICK PLZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
Answer:
D. Atom, Electron, and Proton
Explanation:
Because Atoms are the smallest and they make up everything.
because the Proton, stable subatomic particle that has a positive charge equal in magnitude to a unit of electron charge and a rest mass of 1.67262 × 10−27 kg, which is 1,836 times the mass of an electron.
Answer:
C
Explanation:
Electrons are the smallest part of matter. Protons are bigger than electrons. And the whole atom is bigger than everything inside it.
1.8 x 1022 atoms of Rn to moles of Rn
Answer:
1.8×10²² atom of Rn contain 0.03 moles of Rn.
Explanation:
Given data:
Number of atoms of Rn = 1.8×10²² atoms
Number of moles = ?
Solution:
we will solve this problem through Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
For example,
1 mole of Rn = 6.022 × 10²³ atoms of Rn
1.8×10²² atoms of Rn × 1mol / 6.022 × 10²³ atoms of Rn
0.3×10⁻¹ moles of Rn
0.03 moles of Rn
Fluorescent light bulbs, or CFLs, prevent the loss of energy from light bulbs as ________ energy.
A. Light
B. Electrical
C. Chemical
D. Thermal
Please do mark me as Brainiest. I would be so happy!!! Here's your answer....
Answer:
D.)
Explanation:
Compact fluorescent lamps, or CFLs, use 75 percent less energy than a traditional incandescent bulb, but they never quite caught on for home use.
Have a great rest of your day!
Please help!!!!!!!!!!!
Answer:
They both have two valence electrons
Answer:
I am guessing because they are both metals
0.68 moles of calcium to calcium atoms
[tex]0.68 \: moles \: calcium \times \frac{6.02 \times {10}^{23} \: calcium \: atoms }{1 \: mole \: calcium} \\ [/tex]
The (( mole calcium ))s are simplified so the answer is based on the number of calcium atoms.
[tex]0.68 \times 6.02 \times {10}^{23} = 68 \times {10}^{ - 2} \times 602 \times {10}^{ - 2} \times {10}^{23} \\ [/tex]
[tex] = 68 \times 602 \times {10}^{ - 4} \times {10}^{23} = 40936 \times {10}^{19} \\ [/tex]
[tex] calcium \: atoms = 40936 \times {10}^{19} \\ [/tex]
_________________________________
And we're done.
Thanks for watching buddy good luck.
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are
Why the elements of d-block elements
called transition element?
Answer:
O nome "transição" vem da posição dos elementos na tabela, representando a transição do grupo 2 ao 13, pela sucessiva adição de elétrons ao orbital d. Elementos de transição externa (ou somente elementos de transição):
Consider a cylinder of a gasoline engine at the beginning of the compression cycle, during which a fuel/air mixture (for our purposes mostly composed of nitrogen and oxygen, i.e. an ideal gas of diatomic molecules) at 300 K and 1 bar is compressed down to one-tenth volume (compression ratio of 10:1). Assume that the compression is rapid so no heat exchange occurs with the environment. Calculate the pressure and the temperature of the compressed gas. In a diesel engine the compression ratios are typically much higher; redo the same calculation with the compression ratio of 20:1.
Answer:
(i) Final pressure and temperature are 25.119 bar and 753.566 K, (ii) Final pressure and temperature are 66.289 bar and 994.336 K.
Explanation:
This system experiments an adiabatic compression, as such compression happens with no heat interaction between the piston-cylinder device and surroundings. This is a particular case of polytropic process, in which there is no entropy generation according to the Second Law of Thermodynamics.
The compression process is represented by the following formulas:
[tex]\frac{p_{2}}{p_{1}} = \left(\frac{V_{1}}{V_{2}} \right) ^{\gamma}[/tex] (Eq. 1)
[tex]\frac{T_{2}}{T_{1}} = \left(\frac{V_{1}}{V_{2}} \right)^{\gamma - 1}[/tex] (Eq. 2)
Where:
[tex]p_{1}[/tex], [tex]p_{2}[/tex] - Initial and final pressures, measured in bar.
[tex]T_{1}[/tex], [tex]T_{2}[/tex] - Initial and final temperatures, measured in Kelvins.
[tex]V_{1}[/tex], [tex]V_{2}[/tex] - Initial and final volumes, measured in cubic meters.
[tex]\gamma[/tex] - Specific heat ratio of air, dimensionless.
From Theory of Diesel and Otto Cycles we know that compression ratio is defined as:
[tex]r_{c} = \frac{V_{1}}{V_{2}}[/tex] (Eq. 3)
And (Eqs. 1, 2) can be rewritten as follows:
[tex]\frac{p_{2}}{p_{1}} = r_{c}^{\gamma}[/tex] (Eq. 1b)
[tex]\frac{T_{2}}{T_{1}} = r_{c}^{\gamma - 1}[/tex] (Eq. 2b)
Then, we clear final pressure and pressure in each expression and calculate them for each case:
[tex]p_{2} = p_{1}\cdot r_{c}^{\gamma}[/tex]
[tex]T_{2} = T_{1}\cdot r_{c}^{\gamma-1}[/tex]
(i) [tex]r_{c} = 10[/tex], [tex]p_{1} = 1\,bar[/tex], [tex]T_{1} = 300\,K[/tex], [tex]\gamma = 1.4[/tex]
[tex]p_{2} = (1\,bar)\cdot 10^{1.4}[/tex]
[tex]p_{2} = 25.119\,bar[/tex]
[tex]T_{2} = (300\,K)\cdot 10^{0.4}[/tex]
[tex]T_{2} = 753.566\,K[/tex]
Final pressure and temperature are 25.119 bar and 753.566 K.
(ii) [tex]r_{c} = 20[/tex], [tex]p_{1} = 1\,bar[/tex], [tex]T_{1} = 300\,K[/tex], [tex]\gamma = 1.4[/tex]
[tex]p_{2} = (1\,bar)\cdot 20^{1.4}[/tex]
[tex]p_{2} = 66.289\,bar[/tex]
[tex]T_{2} = (300\,K)\cdot 20^{0.4}[/tex]
[tex]T_{2} = 994.336\,K[/tex]
Final pressure and temperature are 66.289 bar and 994.336 K.
Which of the following are properties of substances with matter? (2 points)
a
Mass and volume
b
Length and width
c
Shape and color
d
Size and texture
Based on what you observed on the link above,
describe how ice in a teapot is turned into steam.
Liquid
lid
Answer: the particles in the water heats up and the hotter to gets the faster it moves. When there is no where for the heat to go it builds up and pushes its way out and turns to steam when it hits cool air
Explanation:
Which of the following is least like the others on the list?
a. Amino acid
b. Ribonucleic acid
c. Nucleic acid
d. Nucleotides
Explanation:
C option i think but I didn't know
A 10.0-g sheet of gold with a temperature of 18.0°C is laid flat on a sheet of iron that weighs 20.0 g and has a temperature of 55.6°C. Given that the specific heats of Au and Fe are 0.129 J g-1 0 c-1 and 0.444 J g-1 0 c-1, respectively, what is the final temperature of the combined metals? Assume that no heat is lost to the surroundings. (Hint: The heat gained by the gold must be equal to the heat lost by the iron.)
Answer:
T = 50.83°C
Explanation:
Let the final temperature be T .
heat lost = mass x specific heat x fall in temperature
heat lost by iron = 20 x .444 x ( 55.6 - T )
heat gained by gold = 10 x .129 x ( T- 18 )
heat lost = heat gained
20 x .444 x ( 55.6 - T ) = 10 x .129 x ( T- 18 )
493.73 - 8.88 T = 1.29 T - 23.22
10.17 T = 516.95
T = 50.83°C
The final temperature of the combined metals (gold and iron) is 50.83°C.
Given the following data:
Initial temperature of gold = 18.0°CFinal temperature of iron = 55.6°CMass of gold = 10.0 gMass of iron = 20.0 gSpecific heat capacity of iron = 0.444 J/g°C.Specific heat capacity of gold = 0.129 J/g°C.To find the final temperature of the combined metals (gold and iron):
Heat lost by the iron = Heat gained by the gold.
[tex]Q_{lost} = Q_{gained}\\\\mc\theta = mc\theta\\\\20(0.444)(55.6 - T_f) = 10(0.129)(T_f - 18)\\\\8.88(55.6 - T_f) = 1.29(T_f - 18)\\\\493.728 - 8.88T_f = 1.29T_f - 23.22\\\\8.88T_f + 1.29T_f = 493.728 + 23.22\\\\10.17T_f = 516.948\\\\T_f = \frac{516.948}{10.17}[/tex]
Final temperature = 50.83°C
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Helpppp fasttttttttttttttt Choose the best word to complete the sentence.
The teacher asked us to determine if the triangle was
a vegetal
C. Vertex
b. equilateral
d. negative space
Please select the best answer from the choices provided
Answer:
equilateral (B)
Explanation:
it is the only word which relates to triangles and their shape - plus, its logical and makes sense.
Answer:
its b
Explanation:
15.0 L of an ideal gas at 298 K and 3.36 bar are heated to 350 K with a new pressure of 4.40 atm. What is the new volume in litres?
Answer:
13.3 L
Explanation:
Step 1: Given data
Initial pressure (P₁): 3.36 barInitial volume (V₁): 15.0 LInitial temperature (T₁): 298 KFinal pressure (P₂): 4.40 atmFinal volume (V₂): ?Final temperature (T₂): 350 KStep 2: Convert P₁ to atm
We will use the conversion factor 1 atm = 1.01325 bar.
3.36 bar × (1 atm / 1.01325 bar) = 3.32 atm
Step 3: Calculate V₂
We will use the combined gas law.
P₁ × V₁/T₁ = P₂ × V₂/T₂
V₂ = P₁ × V₁ × T₂/T₁ × P₂
V₂ = 3.32 atm × 15.0 L × 350 K/298 K × 4.40 atm
V₂ = 13.3 L
how the El Niño event affected the weather, food production, water supply, or human health?
El Niño was responsible for the following events in 2015:
16 tropical cyclones in the central Pacific hurricane basin
three category 4 hurricanes occurred at the same time
emergency water rationed in St. Lucia and San Juan
65 percent of Antigua's farmers went out of business
northern, central, and southeastern Ethiopian highlands received 50–90 percent of their normal rainfal.
Answer:
EL Niño had hurricanes and so many damages in nature. :)
Explanation:
it creates warm weather, there is low pressure towards canada
Numerous health issues, such as disease outbreaks, malnutrition, heat stress, and respiratory illnesses are being brought on by the severe drought and associated food insecurity, flooding, precipitation, and temperature increases brought on by El Nino.
What is El- Nino?The exceptional warming of surface waters in the eastern tropical Pacific Ocean is referred to as El Nino, a climate pattern. El Nino is a bigger phenomena known as the El Nino-Southern oscillation, and it is its warm phase.
Climate change brought on by El Nino can be severe and extensive. Increased precipitation results from convection over warmer surface waters. In Ecuador and northern Peru, rainfall rises dramatically, causing coastal erosion and flooding.
Homes, businesses, schools, and hospitals may be destroyed by heavy rains and flooding. They hinder transportation and obliterate crops. As reservoirs dry up and rivers carry less water, the droughts pose a threat to the area's water resources. Agriculture is in danger since it depends on water for irrigation.
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The graph below represents the relationship between the distance traveled and time elapsed for an object in motion.
During which interval is the speed of the object changing?
Group of answer choices
BC
DE
Answer:
DE
Explanation:
BC has a constant speed of 0, and DE does not have a consistent slope, therefore the speed is changing
The speed is defined as the rate of change of distance with respect to time.
In interval DE , speed of the object is changing.
Since, speed is defined as the rate of change of distance with respect to time.
[tex]v=\frac{dx}{dt}[/tex] , where x represent distance.
Slope of given graph represent distance, In interval BC slope is constant.
In interval, DE slope is always changing at each point.
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