Answer:
When zinc is added to copper sulphate (CUSO4) solution due to more reactivity of zinc, cooper is replaced by the zinc and forms zinc sulphate. During the process, the colour of the solution changes from blue to colourless.
What are precautions to be taken when doing titrations? A-Make sure to always vigorously shake that flask after every drop if the end point is still unknown. It may be that the remaining volume of the titrant needed to reach the end point is just adhering on the wall. This is to ensure accuracy. B-The amounts of solid and liquid should be weighed and pipetted with high accurac This is because all the data that will be produced will mainly depend on this. C- If the end point is unknown, dropwise addition of the titrant is recommended. D- Always make sure that the indicator is added. E- All of the above
Answer:
E
Explanation:
This is because all steps from A-D are important to obtain an accurate result
Am element has 18 electrons ,20 neutrons and a charge of -2.what is the mass number?..a.38 b.40 c.32 d.39
Answer:
Surely you must have a Periodic Table beside you....?
a=38
Explanation:
You gots Z=18, the atomic number, where Z is the number of nuclear protons. The number of protons defines the element....and thus we got calcium....
....and with 20 neutrons we got the 38Ca isotope....the which is rather short-lived...
why hydrogen has dual nature?
Answer:
Since hydrogen has a single electron in its valence shell, it exhibits dual nature. of the periodic table, or it can obtain one electron to complete its valency of two, such as halogens from Group 17. Since it only has one electron in its outer shell, hydrogen has a dual existence.
Explanation:
This means that, like a normal halogen, a hydrogen atom can easily gain an electron to form a complete outer shell, or lose an electron to form an alkali metal. Since it already has two electrons in its outer shell, hydrogen can be diatomic, rendering it unreactive.
Please help thank you (15 points)
Answer:
C.
Explanation:
The arrows represent the Earth spinning on its own axis in this picture.
Which of the following atoms is expected to have two unpaired electrons?
Al
Mg
Na
None of the above
Answer:
none of the above answers
In a year an adult cow produces around 3.571 x 10^27 molecules of methane CH4 a greenhouse gas how many moles of methane does this cow produce in a year
Answer:
[tex]\boxed{\boxed {\sf 5930.0 \ mol \ CH_4}}[/tex]
Explanation:
We are asked to find how many moles of methane (CH₄) a cow produces in a year. We must convert molecules of methane to moles of methane. We will do this using Avogadro's Number or 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance.
In this case, the particles are molecules of methane. There are 6.022 × 10²³ molecules of methane in 1 mole.
We will convert molecules to moles using dimensional analysis. Set up a ratio using Avogadro's Number.
[tex]\frac {6.022 \times 10^{23} \ molecules \ CH_4}{ 1 \ mol \ CH_4}[/tex]
We are converting 3.571 × 10²⁷ molecules of methane to moles, so we multiply the ratio by this value.
[tex]3.571 \times 10^ {27} \ molecules \ CH_4 *\frac {6.022 \times 10^{23} \ molecules \ CH_4}{ 1 \ mol \ CH_4}[/tex]
Flip the ratio. It is still the same value, but the units of molecules of methane cancel.
[tex]3.571 \times 10^ {27} \ molecules \ CH_4 *\frac { 1 \ mol \ CH_4}{6.022 \times 10^{23} \ molecules \ CH_4}[/tex]
[tex]3.571 \times 10^ {27} *\frac { 1 \ mol \ CH_4}{6.022 \times 10^{23} }[/tex]
[tex]\frac {3.571 \times 10^ {27}}{6.022 \times 10^{23} } \ mol \ CH_4[/tex]
[tex]5929.923613 \ mol \ CH_4[/tex]
The original measurement of molecules of methane( 3.571 × 10²⁷ molecules) has 4 significant figures, so our answer must have the same. For the number we calculated, that is the ones place. The 9 in the tenth place tells us to round the 9 in the ones place up to a 0, then the 2 in the tens place up to a 3.
[tex]5930 \ mol \ CH_4[/tex]
We must add a placeholder zero in the tenth place to reach 4 sig figs.
[tex]5930.0 \ mol \ CH_4[/tex]
The adult cow produces approximately 5930.0 moles of methane in a year.
Which property altered during a chemical change is not altered during a physical change?
A. composition of the matter
B. temperature of the matter
C. volume of the matter
D. phase of the matter
The property altered during a chemical change that is not altered during a physical change is composition of the matter.
A physical change is one in which no new substance is formed and it is easily reversible.
A chemical change is one that is not easily reversible and no new substance is formed. It may be accompanied by absorption or evolution of heat.
The composition of a substance changes during a chemical change because bonds between atoms break and new bonds are formed. This does not occur during a physical change.
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Water is placed into a sealed jar and has a mass of 22.0 grams. The jar is placed in the freezer and the water turns to ice. The jar of ice is measured. The mass should be:
a. Slightly less than 22.0 grams
b. Exactly 22.0 grams
c. Slightly more than 22.0 grams
exactly 22.0 grams
because freezing is a physical change not a chemicl change..so nothing is taken away or added
ANSWER;
exactly 22.0 grams
because freezing is a physical change not a chemicl change..so nothing is taken away or added
compared to those
5. Electrons farther away from the nucleus in an atom have
closer to the nucleus.
O A. lower energy
OB. higher energy
O C. the same energy
O D. higher or lower energy, depending on the element
Explanation:
higher or lower energy, depending on the element
Answer:
B
Explanation:
What is 47.35 dL= mL?
Answer:
4.735 litres
Explanation:
10 dL = 1 litre
47.35 dL = 47.35/10 = 4.735 litres
List of choices for questions 20-24: A. (1) CH3MgBr, (2) H3O , (3) CH3MgBr, (4) H3O B. (1) LDA, (2) CH3I, (3) H3O C. (1) CH3MgBr, (2) H3O , (3) NaBH4, (4) H3O D. (1) DIBAH, (2) H3O E. (1) NaOH, heat, (2) SOCl2, (3) CH
Answer:
h30
Explanation:
h = 3.0 a + 28.2
A pediatrician uses the model above to estimate the height h of a girl, in inches, in terms of the girl's age a, in years. Based on the model, what is the estimated height of a 2-year-old girl?
Answer:
h = 34.2 in
Explanation:
h = 3.0a + 28.2
h = height of a girl.
a = age of a girl.
h = 3.0a + 28.2
h = 3.0(2) + 28.2
h = 6 + 28.2
h = 34.2
The estimated height of a 2-year-old girl is 34.2 in.
Hope this helps, thank you :) !!
calculate mass of MnO2 if 1 mole of KMnO4 completely burnt. 2KMnO4 -> K2MnO4+MnO2+O2
Answer: 80 grams
Explanation:
2KMnO4 -> K2MnO4+MnO2+O2
2 moles of KMnO4 would produce 1 mole of MnO2, so 1 mole of KMnO4 would produce 0.5 moles of MnO4. The molar mass of MnO4 is 160 g/mole. 1/2 mole of KMnO4 would therefore be (160 g/mole)*(0.5 moles) = 80 grams.
b. Use the balanced equation to answer the following questions.
CuSO4(aq) + 2NaOH(aq) —->Cu(OH)2(s) + Na2SO4(aq)
i. What is the ratio of moles of CuSO4 to moles of NaOH?
ii. If 638.44 g CuSO4 reacts with 240.0 NaOH, which is the limiting reagent?
iii. Using the limiting reagent to determine how many grams of Cu(OH)2 should precipitate out in the reaction.
iv. If only 174.6g of Cu(OH)2 precipitate were actually collected from the reaction, what would the percent yield be?
Answer:
i. 1 : 2
ii. NaOH is the limiting reagent
iii. 292.5g
iv. 59.69%
Explanation:
I have the detailed and self-explanatory workings. will snap and post later. Battery percent at 15%, flashlight not working.
1. The ratio of CuSO₄ to NaOH is 1 : 2
2. The limiting reactant is NaOH.
3. The mass of Cu(OH)₂ that will precipitate out is 292.5 g.
4. The percentage yield of Cu(OH)₂ is 59.7%
1. Determination of the ratio of CuSO₄ to NaOH.
CuSO₄ + 2NaOH —> Cu(OH)₂ + Na₂SO₄
From the balanced equation above, we can see that the ratio of CuSO₄ to NaOH is 1 : 2
2. Determination of the limiting reactant.
CuSO₄ + 2NaOH —> Cu(OH)₂ + Na₂SO₄
Molar mass of CuSO₄ = 63.5 + 32 + (16×4) = 159.5 g/mol
Mass of CuSO₄ from the balanced equation = 1 × 159.5 = 159.5 g
Molar mass of NaOH = 23 + 16 + 1 = 40 g/mol
Mass of NaOH from the balanced equation = 2 × 40 = 80 g
From the balanced equation above,
159.5 g of CuSO₄ reacted with 80 g of NaOH.
Therefore,
638.44 g of CuSO₄ will react with = (638.44 × 80) / 159.5 = 320.22 g of NaOH.
From the calculations made above, we can see that a higher mass (i.e 320.22 g) of NaOH than what was given (i.e 240 g) is needed to react completely with 638.44 g of CuSO₄.
Therefore, NaOH is the limiting reactant.
3. Determination of the mass of Cu(OH)₂ that will precipitate out.
CuSO₄ + 2NaOH —> Cu(OH)₂ + Na₂SO₄
Molar mass of Cu(OH)₂ = 63.5 + 2(16 + 1) = 97.5 g/mol
Mass of Cu(OH)₂ from the balanced equation = 1 × 97.5 = 97.5 g
From the balanced equation above,
80 g of NaOH reacted to produce 97.5 g of Cu(OH)₂.
Therefore,
240 g of NaOH will react to produce = (240 × 97.5) / 80 = 292.5 g of Cu(OH)₂
Thus, 292.5 g of Cu(OH)₂ precipitated out of the reaction.
4. Determination of the percentage yield.
Actual yield of Cu(OH)₂ = 174.6 gTheoretical yield of Cu(OH)₂ = 292.5 gPercentage yield of Cu(OH)₂ =?Percentage yield = (Actual /Theoretical) × 100
Percentage yield of Cu(OH)₂ = (174.6 / 292.5) × 100
Percentage yield of Cu(OH)₂ = 59.7%
Learn more about percentage yield:
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Hello please I need help
6. Heat from the sun reaches to us by
(a) radiation
(b) conduction
(c) convection
(d) all of these
PS. the one who gets it correct will be followed by me and also be marked as the brainliest!
Answer:
radiation
....
.
.
.
.hi how r u
Is my answer correct
Answer:
Radiation
Explanation:
Heat from the sun reaches is by the process of radiation
Which of these outcomes is conclusive evidence that mixing sugar in water is a physical change?
Answer:
» Water changes from colorless to a pale colored solution.
» The solubility of water reduces because a saturated solution is formed.
» The freezing point of water decreases. [colligative property]
» The boiling point of water elevates [colligative property]
» The vapour pressure of water lowers [colligative property]
Explanation:
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What would most likely happen if the kangaroo rats
were killed off and removed from the food chain?
Answer:
Explanation:
The number of cactus plants would increase.
When a liquid is at its boiling point, the vapor pressure of the liquid
A cation of 2 indicates that an element has Group of answer choices lost two neutrons. lost two protons. gained two electrons. lost two electrons. gained two protons.
Answer:
lost 2 electrons
Explanation:
A cation by definition is a positively charged ion. They are formed when a metal loses its electrons. A cation has more protons than electrons, giving it a net positive charge. So, it had to have lost 2 electrons to give it a positive charge of 2⁺.
Phosphorous-32 has a half life of 14.3 days while radon-222 has a half-life of 3.8 days, so phosphorous-32 is considered more active.
a. True
b. False
The specific gravity of a vegetable oil is 0.92. What is the massgrams, of 330 mL of vegetable oil?
Answer:
HOPE THIS ANSWER WILL HELP YOU
How many atoms are in 0.100 mol of C3H8
Oceanography does not include the study of which of the following topics?
A.the relationship between the Sun, Moon, and Earth
B.the relationship between the atmosphere, Earth, and the oceans
C.the Earth's oceans
D.the plants and animals that live in the oceans
Answer:
A. The relationship between the Sun,Moon,and Earth
Explanation:
Which of the following is a feature of a Type IV flotation device?
Answer:
A Type IV PFD is an approved device designed to be thrown to a person in the water. It is not designed to be worn. It is designed to have at least 16.5 pounds of buoyancy. The most com- mon Type IV PFD is a buoyant cushion.
What is the chemical formula for peracetic acid?
The chemical formula for peracetic acid is C2H4O3. This means that there are 2 atoms of carbon, 4 atoms of hydrogen, and 3 atoms of oxygen in a single molecule.
I think that the answer is C2H4O3.
when two atoms share four valence electrons the shared electrons form a/an ____
How can the Swartz process be modified to work for bacteria? Explain.
Answer:
https://swartzbiotechnologylab.sites.stanford.edu/research
Explanation:
Alkyl chlorides and alkyl bromides are typically transformed into alkyl fluorides in the organic reaction known as the Swarts Reaction.
Swartz reaction?Frederick Jean Edmond Swarts first reported this procedure in 1892. Heating the alkyl chloride or alkyl bromide in the presence of heavy metal fluorides like AGF, Hg2F2, CoF2, or SbF3 causes this reaction.
Swartz process can be used to modify work for bacteria. Bacterial biofilms are collections of microorganisms where the cells are immersed in an extracellular polymeric matrix that the bacteria have self-produced.
In contrast to planktonic bacteria, which are in a state of free movement in a bulk solution, this situation is very different.
Applications:
In this process, alkyl fluorides are created.Fluorinated aliphatic organic molecules, or Freons, are produced via a different variation of the same process.Anhydrous hydrogen fluoride is fluorinated to produce Freons in the presence of antimony salts, which exhibit the oxidation states +3 and +5.Therefore, Alkyl chlorides and alkyl bromides are typically transformed into alkyl fluorides in the organic reaction known as the Swarts Reaction.
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How many inches are in 4.5 miles?
aluminum has a density of 2.70 g/mL. Calculate the mass (in grams) of a piece of aluminum having a volume of 344 mL
Answer:
[tex]\boxed {\boxed {\sf 928.8 \ grams}}[/tex]
Explanation:
Density is the mass per unit volume of a substance. The following formula is used for calculating density.
[tex]\rho= \frac{m}{v}[/tex]
We know the density of aluminum is 2.70 grams per milliliter. The mass is unknown, but we know the piece of aluminum has a volume of 344 milliliters.
ρ= 2.70 g/mL v= 344 mLSubstitute these values into the formula.
[tex]2.70 \ g/mL = \frac {m}{344 \ mL}[/tex]
We are solving for the mass, so we must isolate the variable m. It is being divided by 344 milliliters. The inverse operation of division is multiplication. Multiply both sides of the equation by 344 mL.
[tex]344 \ mL *2.70 \ g/mL = \frac {m}{344 \ mL} * 344 \ mL[/tex]
[tex]344 \ mL *2.70 \ g/mL =m[/tex]
The units of milliliters cancel.
[tex]344 *2.70 \ g=m[/tex]
[tex]928.8 \ g =m[/tex]
The mass of the piece of aluminum is 928.8 grams.
