Answer:
the answer is mostly option a)XCl
Explanation:
4(a) Why doesn't the water flow out when the hand that presses the cardboard is removed? *
1. water inside glass is lighter
2. there is much water inside the glass
3. cardboard is supported by air pressure
4.
cardboard is strong enough to hold the water
Filtration is the most appropriate method for separating a solution of water and which substance?
A. alcohol
B. salt
C. sand
D. sugar
Answer:
Sand
Explanation:
If you get salt or sugar in your water, you have to legit desalinate it to get the water and item out. You need to evaporate the water by increasing temperature and then lower temperature to separate the substances.
If you have alcohol, you need to distill it by trapping it and stuff.
With sand, the molecules are much larger which lets you separate the substances easily.
For example, on a beach, you can slap a handful of sand in your pail, but the sand sinks to the bottom right? You can just pour out the water.
Which is an example of a three
dimensional measurement of
volume?
A. 120 cubic meters
B. 120 grams
C. 120 miles per hour
D. 120 units
Answer:
It's A. 120 cubic meters
calculate the number of moles in 2.5 particle NaOH
Answer:
1.5055×10²⁴
Explanation:
................................
Are ALL acids and based
harmful to humans?
Which of the following represents the electronic structure of three elements in the periodic table
A. 2.8.1 2.8.3 2.8.4 B. 2.8 2.8.1 2.8.2
C. 2.7 2.8 2.8.1 D. 2.1 2.8.1 2.8.8.1
Answer:
a
Explanation:
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Iron has a density of 7.86 g/cm3. Calculate the volume (in dL) of a piece of iron having a mass of 4.59 kg .
Which functional group does the molecule below have?
A. Ether
B. Amino
C. Carbonyl
D. Hydroxyl
SUBV
Answer:
Ether is the correct answer
Explanation:
It is based.
a mixture , the different parts of which vary in composition and properties
Answer:
heterogeneous mixture
Explanation:
(a) A mixture with the same composition and properties throughout is called a homogeneous mixture. (b) A mixture, the different parts of which vary in composition and properties, is called a heterogeneous mixture.
22. Which of the following is contained only in a eukaryotic cell? A. cell wall
B. nucleus
C. chromosomes
23.Which of the following terms represent the chemical reactions to break down food into simpler compounds in an organism?
A. anabolism
B. catabolism
C. nitrogen cycle
24.What types of molecules are bonded together to form a nucleotide? A. 2 nitrogen bases + 1 sugar
B. 2 sugars + 1 phosphate group
C. 1 nitrogen base + 1 phosphate group + 1 sugar
25.Glucose and oxygen are the two products of photosynthesis A. true
B. false
26.What is the first step in the refining of petroleum? A. cracking
B. drilling
C. distillation
27.When radium-226 (atomic number 88) decays by emitting an alpha particle, it becomes _________.
A. polonium-222 B. polonium-224 C. radon-222
28.The general name for hydrocarbons with at least one triple covalent bond is _________.
A. alkenes B. alkanes C. alkynes
29.What particle is emitted in alpha radiation? A. electron
B. photon
C. helium nucleus
30.Which type of compound is this? CH3CH2CH2CH2OH
A. alcohol B. aldehyde C. ether
31.Why are the molecules of hydrocarbons nonpolar? A. The intermolecular attractions are strong.
B. All the bonds are single covalent bonds.
C. The electron pair is shared almost equally in all the bonds.
32. An amino group and a carboxyl group are joined by a ___________ bond. A. peptide
B. protein
C. amino
33.What type of radiation is likely to occur when the ratio of protons to neutrons is below the band of stability?
A. alpha decay
B. beta decay
C. neutron emission
34.Covalent bonds are between bases in a DNA base-pair. A. true
B. false
35.What is the name of the functional group in the following compound? R—NH2
A. halogen B. amine C. ether
Answer:
22 options A cell wall
23 options A anabolism
24 options B 2sugar + 1phosphate group
9. Hydrogen is 99% H, 0.8% ?H, and 0.2% H. Calculate its average atomic mass.
Answer: Technically, this cannot be answered, since none of the H atoms have a mass number assigned. With the assumption noted delow, I calculate 1.012 as the average atomic mass.
Explanation:
My answer is based on assumed masses for the three H isotopes:
1H : 1 AMU
2H: 2 AMU Deuterium
3H: 3AMU Tritium
AMU Rel Abund. Wt. Avg
1H 1 99.00% 0.99
2H 2 0.80% 0.016
3H 3 0.20% 0.006
Sum 1.012
Describe the differences between models and scientific laws and theories. (
Answer:
Scientific laws and theories have different jobs to do. A scientific law predicts the results of certain initial conditions. ... In simplest terms, a law predicts what happens while a theory proposes why. A theory will never grow up into a law, though the development of one often triggers progress on
Explanation:
The mass of an atom of element x is equivalent to the total mass of 7 hydrogen atoms
What are the differences of a physical change and a chemical change?
Answer:
a physical change only changes the look of something whereas a chemical change occurs when one thing has a reaction and it forms a new substance.
Which of the following is an example of a change from gravitational potential
energy to kinetic energy?
Answer:
The speed of a roller coaster increases as gravity pulls it downhill and is greatest at its lowest point. Viewed in terms of energy, the roller-coaster-Earth system's gravitational potential energy is converted to kinetic energy
Explanation:
a ball held in the air is the example of a change from gravitational potential energy to kinetic energy.
Assuming equimolar quantities of reactants, which compound will react to the greatest extent with boron trifluoride (BF3) in a Lewis acid-base reaction
To solve such this we must know the concept of acid-base reaction. Therefore, NH[tex]_3[/tex] is the compound that will react to the greatest extent with boron trifluoride (BF[tex]_3[/tex]) in a Lewis acid-base reaction.
What is chemical reaction?Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.
NH[tex]_3[/tex] is an example of a Lewis Base that will react extensively with BF[tex]_3[/tex] to form the compound NH[tex]_3[/tex] + BF[tex]_3[/tex] → [B (NH[tex]_3[/tex])F[tex]_3[/tex]].
Therefore, NH[tex]_3[/tex] is the compound that will react to the greatest extent with boron trifluoride (BF[tex]_3[/tex]) in a Lewis acid-base reaction.
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Is thallium, TI, a solid, liquid, or gas?
Answer:
Thallium is a Solid
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Which of the following words means "the degree to which a measurement is precise and reliable"?
a. variable
b. accuracy
c. parameter
d. constant
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.
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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:
[tex].[/tex]
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
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
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:
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:
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
What is 47.35 dL= mL?
Answer:
4.735 litres
Explanation:
10 dL = 1 litre
47.35 dL = 47.35/10 = 4.735 litres
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.
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.
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%
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Illustrate the law of law of multiple proportions using the formation of SO2 and SO3 by sulphur and oxygen
As illustrated from law of multiple proportion, the mass of the oxygen which combined with a fixed mass of the sulphur is in simple whole number ratio of 2 is to 3 (2:3).
The law of Multiple proportion states that when two elements combine to form more than one compound, the mass of the second element, which combines with a fixed mass of the first element, will always be ratios of small whole numbers.
To illustrate the law of multiple proportion from sulphur and oxygen, we use the given compounds.
The reaction of oxygen with sulphur to form SO₂ and SO₃:
[tex]S \ + \ O_2 \ -----> SO_2\\\\2SO_2 \ + \ O_2 \ ---> \ 2SO_3[/tex]
atomic mass of oxygen = 16 g
atomic mass of sulphur = 32 g
In the formation of SO₂:mass of sulphur = 32 g and mass of oxygen = (2x16) = 32 g
In the formation of SO₃:mass of sulphur = 32 g and mass of oxygen = (3 x 16) = 48 g
Notice, while mass of sulphur is constant, mass of oxygen changed.
The ratio of mass of oxygen in the given two compounds = 32g : 48g = 2:3
Thus, based on the law of multiple proportion, the mass of the oxygen which combined with a fixed mass of the sulphur is in simple whole number ratio of 2 is to 3 (2:3).
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