How do astronomers know about the future collision of Andromeda and the Milky Way?
A) All galaxies will collide at some point
B) The two galaxies have collided previously
C) Astronomers have observed their movements over time
D) The Milky Way has changed course to head toward Andromeda
Answer:
Astronomers have observed their movements over time
Explanation:
Just took the test!!!
The future collision of Andromeda and milky way are known by astronomers because ; ( C ) Astronomers have observed their movements over time
Andromeda also known as messier 31 is a spiral galaxy that appears as a milky blur when viewed from the earth and it is believed to be slightly over 2.5 million years old.
Astronomers predict that based on its movement and the movement of the Milky way there is most likely going to be a collision in future between the Andromeda and milky way.
Hence we can conclude that The future collision of Andromeda and milky way are known by astronomers because Astronomers have observed their movements over time
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How much K2Cr2O7 is needed to create a saturated solution in 400 grams of water at 50oC?
Answer:
The mass of K₂Cr₂O₇ needed to create a saturated solution in 400 grams of water at 50°C is 120 grams
Explanation:
To answer the question, we will be required to know the solubility of potassium dichromate, K₂Cr₂O₇ in H₂O at 50°C
From the solubility curve, we have, 30 g of K₂Cr₂O₇ will be required to create a saturated solution in 100 g of at 50°C. Therefore, the amount of K₂Cr₂O₇ that will be required to create a saturated solution in 400 g of water, is given by the following equation;
[tex]400 \times \frac{30 \, g \ K_2Cr_2O_7}{100g \ H_2O} = 120 \, g[/tex]
Therefore, the mass of K₂Cr₂O₇ needed to create a saturated solution in 400 grams of water at 50°C = 120 grams.
Answer:
Approximately 128 g of K₂Cr₂O₇ will saturate 400 g of water.
Explanation:
From Literature and solubility curves, the solubility of K₂Cr₂O₇ at 50°C was obtained to be approximately 32 g/100 mL.
Solubility of K₂Cr₂O₇ in water at 50°C = 32 g/100 mL of water
So, how much K₂Cr₂O₇ will dissolve in 400 g of water?
Density of water = 1 g/mL
So, 1 g of water = 1 mL of water
400 g of water = 400 mL of water.
So, if 100 mL of water dissolves 32 g of K₂Cr₂O₇
400 mL of water will dissolve (32 × 4) g of K₂Cr₂O₇, that is, 128 g of K₂Cr₂O₇.
Hope this Helps!!!!
Na2CO3 is a/an ____________ compound where its electrons are _______. *
1.covalent, shared
2.covalent, gained/lost
3.ionic, gained/lost
4.ionic, shared
Answer:
Answer is 3 because NaCo3 because NaCo3 is ionic compound and electrons of ionic compound are gained / lost
Na2O+H2O= 2NaOH how many grams of Na2O are required to produce 1.06*10^2 grams of NaOH
Answer:
77.5 grams of Na2O
Explanation:
Convert grams to mols.
1.06 x 10^2 grams x 1 mol NaOH/39.99
= 2.50 mols NaOH
Find the mole ratio of NaOH and Na2O
1:2
Convert mols NaOH to Na2O mols
2.50 mols NaOH x 1 mol Na2O/2 mols NaOH
= 1.25 mols Na2O
Convert to grams
1.25 mols Na2O x 61.98 grams Na2O/1 mol
= 77.5 grams Na2O required to produce 1.06 x 10^2 grams of NaOH
8. Which of the following energy sources is relatively expensive to set up. but has a low cost once it is in place?
A. natural gas
B. coal
C. nuclear power
D. solar power
If 14 moles of Oxygen burn how many moles of water are created? *
2C2H6
+
702
4CO2 + 6 H2O
A) 12 mol H20
B) 3.5 mol H20
C) 3 mol H20
D) 42 mol H20
Answer:
A) 12 mol H2O.
Explanation:
Hello,
In this case, for the given reaction:
[tex]2C_2H_6+7O_2\rightarrow 4CO_2 + 6 H_2O[/tex]
We notice that oxygen is in a 7:6 molar relationship with water, for that reason, the resulting moles of water turn out:
[tex]n_{H_2O}=14molO_2*\frac{6molH_2O}{7molO_2} \\\\n_{H_2O}=12molH_2O[/tex]
Thus, the answer is A) 12 mol H2O.
Best regards.
PLEASE HURRY
Which substance loses electrons in a chemical reaction?
A.the one that is oxidized, which is the oxidizing agent
B.the one that is reduced, which is the reducing agent
C.the one that is oxidized, which is the reducing agent
D.the one that is reduced, which is the oxidizing agent
Answer:
4) the one that is reduced, which is the oxidizing agent
Explanation:
An oxidizing agent is one that causes oxidation by gaining electrons from another atom/molecule.
Answer:
c
Explanation:
A sample of diborane gas has a pressure of 345 torr at a temperature of -15c and volume of 3.48L if conditions are changed so that the temperature is 36c and the pressure is 468 torr what will be the volume of the sample
Answer: 3.05L= V2
Explanation:
using
P1V1/T1=P2V2/T2
where p1= 345torr
T1, tempertaure= -15c+ 273=258K
T2, temperature= 36+ 273=309K
p2, Pressure= 468 torr
V2=???
P1V1/T1=P2V2/T2
v2=P1V1T2/T1P2= 345X3.46L X 309/ 258X 468=
V2= 3.05L
Identify earths lithospheric plates
Answer:
Lithospheric plates are regions of Earth's crust and upper mantle that are fractured into plates that move across a deeper plasticine mantle. Earth's crust is fractured into 13 major and approximately 20 total lithospheric plates.
Explanation:
I hope this helps
La aspirina se prepara haciendo reaccionar ácido salicílico con exceso de anhídrido etanoico. En un experimento, 50.05 g de ácido salicílico se convirtieron en 55.45 g de aspirina. ¿Cuál fue el porcentaje de rendimiento?
La aspirina se prepara haciendo reaccionar ácido salicílico con exceso de anhídrido etanoico. En un experimento, 50.05 g de ácido salicílico se convirtieron en 55.45 g de aspirina. ¿Cuál fue el porcentaje de rendimiento?
In English:
Aspirin is prepared by reacting salicylic acid with excess ethanoic anhydride. In one experiment, 50.05 g of salicylic acid was converted to 55.45 g of aspirin. What was the yield percentage?
Answer:
el rendimiento porcentual para la cantidad dada de ácido salicílico es 84.99 %
In English:
the percent yield for the given amount of salicylic acid is 84.99%
Explanation:
La ecuación química equilibrada para la reacción se puede escribir como:
C₇H₆O₃ + C₄H₆O₃ → C₉H₈O₄ + HC₂H₃O₂
Para la reacción mostrada arriba; El reactivo limitante de la reacción es el ácido salicílico. Ahora; calcular el porcentaje de rendimiento; se espera que primero determinemos el rendimiento teórico de la reacción.
Entonces; la fórmula para calcular el porcentaje de rendimiento: [tex]\mathbf {= \frac{actual \ yield }{theoretical \ yield } *100 }[/tex]
El rendimiento teórico se determina de la siguiente manera:
50.05 g * 1 mol / 138.21 g / mol de C₇H₆O₃ * 1 mol de C₉H₈O₄ / 1 mol de C₇H₆O₃ * 180.157 g / mol de C₉H₈O₄ = 65.24 g de C₉H₈O₄
Porcentaje de rendimiento [tex]\mathbf {= \frac{55.45 }{65.24 } *100 }[/tex]
Porcentaje de rendimiento = 84.99%
Por lo tanto, el porcentaje de rendimiento para la cantidad dada de ácido salicílico es 84.99%
In English:
The balanced chemical eqaution for the reaction can be written as:
C₇H₆O₃ + C₄H₆O₃ → C₉H₈O₄ + HC₂H₃O₂
For the reaction shown above; The limiting reactant from the reaction is salicylic acid. Now; to calculate the percentage yield ; we are expected to first determine the theoretical yield of the reaction.
So; the formula for calculating the percentage yield [tex]\mathbf {= \frac{actual \ yield }{theoretical \ yield } *100 }[/tex]
The theoretical yield is determined as follows:
50.05 g * 1 mol/ 138.21 g/mol of C₇H₆O₃ * 1 mol of C₉H₈O₄/ 1 mol of C₇H₆O₃ * 180.157 g/mol of C₉H₈O₄ = 65.24 g of C₉H₈O₄ is produced
Percentage yield [tex]\mathbf {= \frac{55.45 }{65.24 } *100 }[/tex]
Percentage yield = 84.99%
Thus, the percent yield for the given amount of salicylic acid is 84.99%
water is a highly polar molecule with strong hydrogen bonding. one of the results of this is that water can climb up a narrow tube. the phenomenom is known as:
A. catapult action (aka trebuchet onfire)
B. capillary action
C. carpel tunnel syndrom
D. capitalization
Answer:
Option B, Capillary action
Explanation:
Water molecules attach with the molecules of the surface of the container in which they are kept. This is because of the cohesive force within the molecules of water and adhesive force between the molecules of water and other substances.
The water rises up in a capillary tube because of water molecules adhere at the edges thereby creating a meniscus in the upside turned direction. The surface is kept intact by the surface tension
Now capillary action specifically occurs when adhesion to the surface of the container is higher than the cohesion between the water molecules.
Hence, option B is correct
According to one acid-base theory a molecule acts as an acid when the molecule
PLEASE ANSWER ASAP- 2 MIN LEFT
A pH of 7 indicates that a solution is ___________ ; a ph <7 would mean the solution is ____________________; and a pH >7 is a(n) ---------- solution.
Answer:
neutral, acidic, basic
Explanation:
Know the acidity rules. Sorry I just saw this!
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Calculate the pressure using the formula P=1.03+ mass on syringe/area of top of syringe
Answer:1.08
Explanation:
Answer:
1.08kg/cm^2
Explanation:
Edge2021
The diameter of a circular swimming pool is 12 feet. Find circumference Round to the nearest tenth . Use 3.14 for pi
Answer:
the pool's circumference is 37.7 ft^2 (rounded to nearest tenth).
* I’ll give you brainlist* The skeletal system has many functions. Which of the following body functions does the skeletal system NOT do?
Answer:
A) remove germs from the blood
Explanation:
cause the rest are the skeletal system function
Answer:
The skeletal system does not remove germs from the blood
Explanation:
I learned that from my teacher
If O2(g) reacts with H2(g) to produce H2O, what is the volume of H2O obtained from 1 L of O2?
Hint: Write a balanced equation first!
Answer:
2L
Explanation:
We'll begin by writing the balanced equation for the reaction this is illustrated below:
2H2 + O2 —> 2H2O
1 mole of a gas occupy 22.4L.
1 mole of O2 occupy 22.4L.
2 moles of H2O occupy = 2 x 22.4 = 44.8L.
From the balanced equation above,
22.4L of O2 produced 44.8L of H2O.
Therefore, 1L of O2 will produce = 44.8/22.4 = 2L.
Therefore, 1L of O2 will produce 2L of H2O.
Which characteristic most likely describes the water in Lake Taal?
Select the correct answer.
o The water will appear slightly red.
O The water will have a slippery feel.
The water will taste bitter.
The water will taste sour.
Answer: The water will taste sour.
Explanation:
Answer: D. The water will taste sour (Edmentum)
Explanation:
In an experiment, 10.6 grams of steam is produced and then cooled. If the heat of vaporization is 2,257 joules/gram, how much energy is released after all the vapor turns to liquid?
Answer:
23,900 joules
Explanation:
plato answer
Answer:
23,900 joules
Explanation:
Edmentum
(Multiple Choice, 30 pts)
A student thinks that halogens are highly reactive because their electrons are weakly attracted to their nuclei. Which is evidence that disputes this student's idea?
A. Halogens react with alkali metals.
B. Halogens cannot react with noble gases.
C. Halogens tend to attract electrons when bonding.
D. Halogens have a full octet of electrons.
Answer:
c
Explanation:
¨Halogens being non metals have greater electronegativities hence, attract electrons and making the statement disputed. Nobel gases are highly stable; this explains why they are nonreactive. They do not form chemical bonds because they only have a little tendency to either gain or lose an electron; on the other hand, halogens are reactive because they only need one additional electron to complete their octet. ¨
i found that from another users answer for the same question
Answer:
answer c
Explanation:
I am at the centre of the atom and contain both neutrons and protons. What am I?
and
Complete the sentence:
Atoms have no overall
charge because...
Answer:
Nucleus and atoms have no overall charge because each element has the same number of protons and electrons which cancel out each other.
help me name the molecule
Answer:
ether
Explanation:
ether is -OR
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if 31.6 g of KMnO4 is dissolved in enough water to give 160 mL of solution, what is the molarity?
AND
what mass of oxalic acid , H2C204, is required to make 300 mL of a .74 M solution?
Answer:
A. 1.25M
B. 19.98g
Explanation:
A. Data obtained from the question include the following:
Mass of KMnO4 = 31.6 g
Volume = 160 mL
Molarity =..?
We'll begin by calculating the number of mole KMnO4 in the solution. This is can be obtained as follow:
Mass of KMnO4 = 31.6 g
Molar mass of KMnO4 = 39 + 55 + (16x4) = 158g/mol
Number of mole of KMnO4 =..?
Mole = mass /Molar mass
Number of mole of KMnO4 = 31.6/158 = 0.2 mole
Now, we can obtain the molarity of the solution as follow:
Volume = 160 mL = 160/1000 = 0.16L
Mole of KMnO4 = 0.2 mole
Molarity = mole /Volume
Molarity = 0.2/0.16 = 1.25M
B. Data obtained from the question include the following:
Volume = 300mL
Molarity = 0.74 M
Mass of H2C2O4 =..?
First, we shall determine the number of mole H2C2O4. This is illustrated below:
Volume = 300mL = 300/1000 = 0.3L
Molarity = 0.74 M
Mole of H2C2O4 =?
Mole = Molarity x Volume
Mole of H2C2O4 = 0.74 x 0.3
Mole of H2C2O4 = 0.222 mole
Now, we can easily find the mass of H2C2O4 by converting 0.222 mole to grams as shown below:
Number of mole of H2C2O4 = 0.222 mole
Molar mass of H2C2O4 = (2x1) + (12x2) + (16x4) = 2 + 24 + 64 = 90g/mol
Mass of H2C2O4 =..?
Mass = mole x molar mass
Mass of H2C2O4 = 0.222 x 90
Mass of H2C2O4 = 19.98g
ionic compounds conduct electricity in the solid state true or false
In solid form, ionic compounds do not conduct electricity. Ionic compounds will conduct electricity when melted to their liquid state. This is due to the electrons being locked in place when in solid form, but liquid form allows for the electrons to move freely.
1. An airplane flew from San Francisco to Washington, D.C.
Approximately halfway through the flight, the plane had traveled 2,000
km in 2.5 hours. What was the speed during this period?
Why might you have difficulty determining the pH of bleach using ph strips?
Answer:
pH test strips will lose colour and their pH sensitivity as strips are made from universal indicator. Universal indicator is composed of phenolphthalein, methyl red, methyl orange and thymol blue.
Explanation:
pH test strips are made from the universal indicator. The universal indicator is composed of phenolphthalein, methyl red, methyl orange, and thymol blue. All of these will react with chlorine in bleach. As a result, they will lose color and pH sensitivity. Due to this, it is difficult to determine the pH of bleach using ph strips.
What are the four main parts of the Sun? *
Answer: The inner layers are core, radiative zone, and convective zone. The putter layers a photosphere, the chromosphere, the transition region and the corona
CHEM HELP PLS 30 POINTS!!
1. what volume of 0.20 M HCl (aq) is needed to titrate 50 mL of 0.10 M NaOH to the endpoint?
A) 10.0 mL HCl
B) 40.0 mL HCl
C) 25.0 mL HCl
D) 20.0 mL HCl
2. what is the molarity of a NaOH solution if 40 mL of the solution is titrated to the endpoint with 15 mL of 1.50 M H2SO4?
A) 1.13 M
B) 1.47 M
C) 0.56 M
D) 0.75 M
3. suppose that 10.0 mL of HNO3 is neutralized by 71.4 mL of a 4.2 x 10 ^ -3 M solution of KOH in a titration. Calculate the concentration of the HNO3 solution.
A) 1.0 x 10 ^ -2 M
B) 3.0 x 10 ^ -2 M
C) 5.5 x 10 ^ -2 M
D) 1.0 x 10 ^ -14 M
Balanced equation
HCl + NaOH —> NaCl + H₂O
From the balanced equation above,
The mole ratio of the acid, HCl (nA) = 1The mole ratio of the base, NaOH (nB) = 1From the question given above, the following data were obtained:
Volume of base, NaOH (Vb) = 50 mLConcentration of base, NaOH (Cb) = 0.1 MConcentration of acid, HCl (Ca) = 0.2Volume of acid, HCl (Va) =?CaVa / CbVb = nA / nB
(0.2 × Va) / (0.1 × 50) = 1
(0.2 × Va / 5 = 1
Cross multiply
0.2 × Va = 5
Divide both side by 0.2
Va = 5 / 0.2
Va = 25 mL (Option C)
2. How to determine the molarity of NaOHBalanced equation
H₂SO₄+ 2NaOH —> Na₂SO₄ + 2H₂O
From the balanced equation above,
The mole ratio of the acid, H₂SO₄ (nA) = 1The mole ratio of the base, NaOH (nB) = 2From the question given above, the following data were obtained:
Volume of base, NaOH (Vb) = 40 mLConcentration of acid, H₂SO₄ (Ca) = 1.5 MVolume of acid, H₂SO₄ (Va) = 15 mL Concentration of base, NaOH (Cb) =?CaVa / CbVb = nA / nB
(1.5 × 15) / (Cb × 40) = 1 / 2
22.5 / (Cb × 40) = 1 / 2
Cross multiply
Cb × 40 = 22.5 × 2
Divide both side by 40
Cb = (22.5 × 2) / 40
Cb = 1.13 M (Option A)
3. How to determine the molarity of HNO₃Balanced equation
HNO₃ + KOH —> KNO₃ + H₂O
From the balanced equation above,
The mole ratio of the acid, HNO₃ (nA) = 1The mole ratio of the base, KOH (nB) = 1From the question given above, the following data were obtained:
Volume of base, KOH (Vb) = 71.4 mLConcentration of base, KOH (Cb) = 4.2×10¯³ MVolume of acid, HNO₃ (Va) = 10 mL Concentration of acid, HNO₃ (Ca) =?CaVa / CbVb = nA / nB
(Ca × 10) / (4.2×10¯³ × 71.4) = 1
(Ca × 10) / 0.29988 = 1
Cross multiply
Ca × 10 = 0.29988
Divide both side by 10
Ca = 0.29988 / 10
Ca = 3×10¯² M (Option B)
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A gas occupies 11.2 liters at 0.860 atm. What is the pressure if the volume is doubled?
Answer:
.43 atm
Explanation:
11.2 x .860 = ans./22.4
We can check this by knowing that P and V at constant T have an inverse relationship. Therefore, this answer is correct.
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On May 3, Zirbal Corporation purchased 4,500 shares of its own stock for $36,000 cash. On November 4, Zirbal reissued 800 shares of this treasury stock for $7,200. Prepare the May 3 and November 4 journal entries to record Zirbal's purchase and reissuance of treasury stock.
Answer:
Explanation:
Each share costs $36000/4500
= $8
800 shares will cost 800*8
= $6400
Find attached the journal
