Which of the following do scientists use to form a hypothesis?

A.
A question and observations

B.
A conclusion and data

C.
A conclusion and a theory

D.
A question and opinions
Explanation:
The scientific method involves making observations and asking questions. Scientists form hypotheses based on these observations and then develop controlled experiments to collecting and analyze data. Using this data, they are able to draw conclusions and form questions for new scientific research.
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How many moles are in 20.0g of lithium?
Answer:
I believe it is 5.00
Explanation:
Zinc metal reacts with copper sulfate through the following
reaction:
Zn + CuSO4 → Cu + ZnSO4
The percent yield for a reaction in which 32.5 g of Zn is reacted
in excess CuSO4 solution is 85.0 %. What is the actual yield of
copper of this reaction?
g
Answer:26.9
Explanation:
What enzyme catalyses the reaction of PRPP transfer to hypoxanthine with
formation of IMP?
Answer:
HPRT
Explanation:
HPRT catalyzes the salvage reactions of hypoxanthine and guanine with PRPP to form IMP and GMP
The formation of GMP from IMP requires oxidation at C-2 of the purine ring, followed by a glutamine-dependent amidotransferase reaction that replaces the oxygen on C-2 with an amino group to yield 2-amino,6-oxy purine nucleoside monophosphate, or as this compound is commonly known, guanosine monophosphate.
Given the reaction
3 H3PO4 + 2 Ba(OH)2 ⇒ BaPO4 + 6 H20
How many grams of precipitate could you make if you reacted 286.0 mL of 3.000 M H3PO4 with 855.0 mL of 1.400 M Ba(OH)2
Answer:
240.17 g Ba3(PO4)2
Explanation:
1. Determine the limiting reactant.
2H3PO4 + 3Ba(OH)2 --> Ba3(PO4)2 + 6H2O
moles H3PO4 = M x V = 3 x 0.286 = .858 moles H3PO4
moles Ba(OH)2 = M x V = 1.4 x 0.855 = 1.197 moles Ba(OH)2
ratio Ba(OH)2 : H3PO4 = 1.197: .858 = 1.39: 1
stoichiometric ratio Ba(OH)2 : H3PO4 = 3:2
Ba(OH)2is the limiting reactant
MM Ba3(PO4)2 = 601.92 g/mol
g Ba3(PO4)2 = moles Ba(OH)2 x(1 mol Ba3(PO4)2/3 moles Ba(OH)2) x (MM Ba3(PO4)2/ 1mol Ba3(PO4)2) = 1.197 x 1/3 x 601.92 = 240.17 g Ba3(PO4)2
What is the number of moles in 125ml of 0.25 M NaNO3solution?
Answer:
0.0313 mole.
Explanation:
From the question given above, the following data were obtained:
Volume of solution = 125 mL
Molarity of NaNO₃ = 0.25 M
Number of mole of NaNO₃ =?
Next, we shall convert 125 mL to litre (L). This can be obtained as follow:
1000 mL = 1 L
Therefore,
125 mL = 125 mL × 1 L / 1000 mL
125 mL = 0.125 L
Thus, 125 mL is equivalent to 0.125 L.
Finally, we shall determine the number of mole of NaNO₃ in the solution. This can be obtained as follow:
Volume of solution = 0.125 L.
Molarity of NaNO₃ = 0.25 M
Number of mole of NaNO₃ =?
Molarity = mole / Volume
0.25 = mole of NaNO₃ / 0.125
Cross multiply
Mole of NaNO₃ = 0.25 × 0.125
Mole of NaNO₃ = 0.0313 mole.
Balance equation mg3n2+h2so4=mgso4+(nh4)2
Answer:
Mg₃N₂ + 4 H₂SO₄ ⇒ 3 MgSO₄ + (NH₄)₂SO₄
Explanation:
To balance an equation, you need to make both sides of the equation have equal number of each element. Also, I think that you didn't write the whole equation since the reaction you gave is not likely.
Mg₃N₂ + 4 H₂SO₄ ⇒ 3 MgSO₄ + (NH₄)₂SO₄
Which one of the following statements about the carbon phosphorus and nitrogen cycles is true ?
a. The major source of carbon used by plants is the soil
b. The major source of nitrogen used by plants is the air.
c. Phosphorus has no atmospheric component.
d. Bacteria drive the phosphorus cycle.
Answer: The correct option is C.
Phosphorus has no atmospheric component.
Explanation:
This is because, phosphorus is not in gaseous state but it is liquid at normal temperature, therefore it cannot be found in the air. It is cycle through water,soil or sediments. The major source of phosphorus in the phosphorus cycle is the rock. Rock contain phosphorus and phosphorus I'd gotten from rocks through weathering. Weathering is the disintegration of rocks into sediments or smaller particles. This is released into the soil after weathering.
Chemical energy is released when bonds blank in a chemical reaction
Answer:
form
Explanation:
hi, if your looking for extra points (50+) and brainiest here is ur chance, answer this question correctly plz
Its the warm air what helps them also of energy of the sun
milk milk milk........
Answer:
gimme that chocky milk.....
Explanation:
Answer:
m i l k
Explanation:
Which statement describes a chemical property of sodium
A Sodium changes from a solid to liquid at a temperature of 97.8°C
B Sodium has the ability to react with chlorine and from a new substance.
C Sodium has destiny if 0.97 g/cm3.
D Sodium takes the form of a solid at room temperature
Answer:
Option b is show the chemical property of sodium....
Need QUICK ANSWERS!!!!!!!!!!!!!!!!!!
Answer: 125.0964 g
Explanation:
Density = mass/volume
Density = 2.7 gcm-3
Volume = 2.7*14.3 = 46.332
Mass=?
Mass= density*volume
= 2.7 x 46.332 = 125.0964 g
Hope this helps! :)
why do you think season will impact the size of a rabbit population
Fossil fuels are made up of organisms that died millions of years ago. Which best describes this source of energy
1. why do the elements within a group of the periodic table have similar chemical properties?
Answer:
the elements in a group have similar electron configurations, an elements electron configuration determines its chemical properties, therefore members of a group in the periodic table have similar chemical properties. ... These metals have a single valence electron and are extremely reactive.
Explanation:
Answer:
Because they all have one or more atoms of the same type material
Explanation:
How does each structure of a sperm cell contribute to the sperm's function?
Tris is a molecule that can be used to prepare buffers for biochemical experiments. It exists in two forms: Tris (a base) and TrisH (an acid). The MW of Tris base is 121.14 g/mol; the MW of TrisH is 157.6 g/mol (the extra weight is due to the Cl- counterion that is present in the acid). The Ka of the acid is 8.32 X 10-9. Assume that you have TrisH in solid form (a powder), unlimited 1M HCl, unlimited 1 M NaOH and an unlimited supply of distilled water. How would you prepare 1 L of a 0.02 M Tris Buffer, pH
Solution :
The reaction :
[tex]$\text{TrisH}^+ + \text{H}_2\text{O} \rightarrow \text{Tris}^- +\text{H}_3\text{O}^+$[/tex]
We have
[tex]$K_a = \frac{[\text{Tris}^-]\times[\text{H}_3\text{O}^-]}{[\text{TrisH}^+]}$[/tex]
[tex]$=\frac{x^2}{0.02-x}$[/tex]
[tex]$= 8.32 \times 10^{-9}$[/tex]
Clearing x, we have [tex]$x=1.29 \times 10^{-5}$[/tex] moles of acid
Now to reach pH = [tex]$7.8 (\text{ pOH} = 14-7.8 = 6.2)$[/tex], we must have an [tex]$OH^-$[/tex] concentration of
[tex]$[OH^-] = 10^{-pOH}$[/tex]
[tex]$=10^{-6.2}$[/tex]
[tex]$=6.31 \times 10^{-7}$[/tex] moles of base
We must add enough NaOH of 1 M to neutralize the acid calculated above and also add the calculated base.
[tex]$n \ NaOH = 1.29 \times 10^{-5} + 6.31 \times 10^{-7}$[/tex]
[tex]$=1.35 \times 10^{-5}$[/tex] moles
Vol [tex]$NaOH = 1.35 \times 10^{-5} \text{ moles} \times \frac{1000 \ mL}{1 \ mol}$[/tex]
= 0.0135 L
Tris mass [tex]$H^+ = 0.02 \text{ mol} \times 157.6 \ g/mol$[/tex]
= 3.152 g
To prepare the said solution we must mix
-- [tex]$3.152 \ g \text{ TrisH}^+$[/tex]
-- [tex]$0.0135 \ mL \ NaOH \ 1M$[/tex]
-- [tex]$\text{Gauge to 1000 mL with H}_2\text{O}$[/tex]
Calculate the pH of each of the following aqueous solutions. (Enter your answers to two decimal places.) (a) 10.0 mL deionized water WebAssign will check your answer for the correct number of significant figures. 2.72 Incorrect: Your answer is incorrect. (b) 10.0 mL deionized water plus 5.0 mL of 0.10 M NaOH WebAssign will check your answer for the correct number of significant figures. (c) 10.0 mL deionized water plus 10.0 mL of 0.10 M NaOH WebAssign will check your answer for the correct number of significant figures. (d) 10.0 mL deionized water plus 15.0 mL of 0.10 M NaOH WebAssign will check your answer for the correct number of significant figures.
Answer:
a. pH = 7.0
b. pH = 12.52
c. pH = 12.70
d. pH = 12.78
Explanation:
a. Deionized water has the [H⁺] of pure water = 1x10⁻⁷ (Kw = 1x10⁻¹⁴ = [H⁺][OH⁻] - [H⁺] = [OH⁻ -)
pH = -log[H⁺] = 7
b. Moles NaOH = 5x10⁻³L * (0.10mol / L) = 5x10⁻⁴moles OH⁻ / 0.015L = 0.0333M = [OH⁻]
-Total volume = 10mL+5mL = 15mL = 0.015L
pOH = -log[OH⁻] = 1.48
pH = 14-pOH
pH = 12.52
c. Moles NaOH = 0.010L * (0.10mol / L) = 1x10⁻³moles OH⁻ / 0.020L = 0.0500M = [OH⁻]
-Total volume = 10mL+10mL = 20mL = 0.020L
pOH = -log[OH⁻] = 1.30
pH = 14-pOH
pH = 12.70
d. Moles NaOH = 0.015L * (0.10mol / L) = 1.5x10⁻³moles OH⁻ / 0.025L = 0.060M = [OH⁻]
-Total volume = 10mL+15mL = 25mL = 0.025L
pOH = -log[OH⁻] = 1.22
pH = 14-pOH
pH = 12.78
I need help with this chem problem!
Analysis: Consider Joe's story. IF the test shows he does have Marfan syndrome, and if he inherited the Marfan gene from his mother, does this mean that his brother and sister also have it? You may want to draw up a Punnett Square or drawing to help you explain your answer. HINT: Is there any suggestion that he got a Marfan gene from his father?
We inherit genes from our biological parents in specific ways. One way is called autosomal dominant inheritance.
What is autosomal dominant inheritance?
Autosomal dominant inheritance means that the gene in question is located on one of the autosomes. These are numbered pairs of chromosomes, 1 through 22. (These chromosomes do not determine an offspring's gender.) Dominant means that only one gene from one parent is necessary to pass down a trait or a disorder. When a parent has a dominant trait or disorder, there is a 50 percent chance that any child he or she has will also inherit the trait or disorder:
Genetic illustration demonstrating autosomal dominant inheritance
Click Image to Enlarge
What is Marfan syndrome?
Marfan syndrome occurs in one of 5,000 live births. It is a connective tissue disorder associated with autosomal dominant inheritance. Connective tissue is abundant in the body and is important as a supporting structure. It is especially important for the musculoskeletal system. It also provides support for other body systems as well, including the eyes and the heart. The gene for Marfan syndrome is called fibrillin-1. This gene is localized to chromosome #15 on the long arm (q) at 15q21.1.
Common findings in individuals with Marfan syndrome include those related to connective tissue disorders. These include abnormal enlargement of the aortic root of the heart, dislocated lenses of the eyes, and a tall, lanky body with increased joint mobility, scoliosis, long flat feet, and long fingers. Findings may vary among individuals diagnosed with this condition, even within a family.
If an individual carries an abnormal gene for Marfan syndrome, that individual has a 50 percent risk of passing down the disorder to each future offspring. If a person does not carry the gene abnormality, then the risk for occurrence of the disorder in future offspring is the same as for the general population.
Explanation:
How many grams of air are required to complete the combustion of 120 g of phosphorous to diphosphorous pentoxide, assuming the air to be 23% oxygen by mass?
Answer:
Explanation:
522 g
Explanation:
Your starting point here will be the balanced chemical equation for this combustion reaction
4
P
(s]
+
5
O
2(g]
→
2
P
2
O
5(s]
Notice that you have a
4
:
5
mole ratio between phosphorus and oxygen. This means that, regardless of how many moles of phosphorus you have, the reaction will always need
5
4
time more moles of oxygen gas.
Use phosphorus' molar mass to determine how many moles you have in that
93.0-g
sample
93.0
g
⋅
1mole P
30.974
g
=
3.0025 moles P
Use the aforementioned mole ratio to determine how many moles of oxygen you would need for many moles of phosphorus to completely take part in the reaction
3.0025
moles P
⋅
5
moles O
2
4
moles P
=
3.753 moles O
2
Which of this is formed when a metal reacts with steam ? *
Carbon dioxide
A Salt
An oxide
A metal hydroxide
A substance that dissolves in a solvent is said to be a(n)
A. immiscible
B. miscible
C. soluble
D. insoluble
Answer:
C. soluble
Explanation:
Remember that a substance that dissolves in a solvent is said to be soluble in that solvent. A substance that does not dissolve in a solvent is insoluble. Process of Dissolving: Solvent particles surround solute particles to form a solution in a process called solvation.
identify the conjugate acid-base H20 (i) + CH3NH2(aq) —> OH-(ag)+ CH3NH3-(ag)
A. taste. B. turns. C. react. D. neutr. E. react. Which is t. A. OH. -. B. H2O ... acids are e conjugate. BANK] w.kau.edu.sa. ______ acid-base p a/aasiri2 1 ... Identify th. HCO. A. H2O. B. HCO. C. H2CO. D. PO4. 3. E. none. Identify th ... (aq) + HCN(aq) → H2O(aq) + CN. -. (aq). D. HCN(aq) + CH3NH2(aq) → CH3NH3. +. (aq)+ CN.
Oxygen gas was produced in a reaction and collected over water. A 136.1 mL mL sample of gas was collected over water at 25C and 1.06 atm. The vapor pressure of water is 23.76 mmHg at 25C. Find the mass of ocygen gas collected in a reaction and collected over water. A 136.1 mL sample of gas was collected over water at 25C and 1.06 atm. The vapor pressure of water is 23.76 mmHg at 25C. Find the mass of oxygen gas collected.
Answer:
Explanation:
We shall find volume of gas at NTP or at 273 K , 760 mm of Hg .
Pressure of given gas = 1.06 x 760 mm of Hg less vapor pressure of water .
= 805.6 - 23.76 = 781.84 mm of Hg
For it we use gas law formula ,
P₁V₁ / T₁ = P₂V₂ / T₂
781.84 x 136.1 / ( 273 + 25 ) = 760 x V₂ / 273
= 128.26 mL .
= 128.26 x 10⁻³ L .
22.4 L of oxygen will have mass of 32 g
128.26 x 10⁻³ L of oxygen will have mass of 32 x 128.26 x 10⁻³ / 22.4 g
= 183.22 mg .
Generally, atmospheric pressure decreases by 1.00 mmHg as
altitude increases 10.0 m. If altitude increases 100. m, how
much would the atmospheric pressure change in atm?
Answer:
-0.0132 atm
Explanation:
Step 1: Calculate the atmospheric pressure change if altitude increases 100. m
Atmospheric pressure decreases by 1.00 mmHg as altitude increases 10.0 m. The decrease in pressure when the altitude increases 100. m is:
100. m × (-1.00 mmHg/10.0 m) = -10.0 mmHg
Step 2: Convert "-10.0 mmHg" to atm
We will use the conversion factor 1 atm = 760 mmHg.
-10.0 mmHg × 1 atm/760 mmHg = -0.0132 atm
What is the concentration of a 22.35 L solution that contains 9.95 moles of sodium
acetate? Round your answer to the correct number of significant figures.
Answer:
0.445 M
Explanation:
Molarity = moles/Volume
M = 9.95/22.35 = 0.445 M
If a pure compound is distilled, the head temperature will be____compared to the pot temperature. If however, an impurity is present that strongly interacts with the liquid molecules, then the____has to be increased in order to increase the vapor pressure of the liquid, ultimately to____atmospheric pressure, allowing the liquid to boil. Thus, at boiling point, the pot temperature will be____from that of the head temperature.
Answer:
If a pure compound is distilled, the temperature of the head will be compared to the temperature of the pot. However, if there is an impurity present that strongly interacts with the molecules of the liquid, then the temperature must be increased to increase the vapor pressure of the liquid, eventually to atmospheric pressure, allowing the liquid to boil. Therefore, at the boiling point, the temperature of the pot will be higher than the temperature of the head.
Explanation:
when temperatures increase, pressures also do so, thus reaching boiling points where liquid states become gaseous.
Use the solubility rules from the Lab 4 introduction and your knowledge of qualitative separation schemes from the lab to answer the following questions. The qualitative analysis experiment you did is actually an abbreviated version of a much larger analysis scheme in which many different cations are separated and identified. Suppose a mixture contains Ag , K , NH4 , Hg22 , Pb2 , Mg2 , Sr2 , Ba2 , Cu2 , Al3 and Fe3 .
(a) Which of the following ions could you separate, by causing them to precipitate, with the addition of HCl?
Ag+ K+ NH4+
Hg22+ Pb2+ Mg2+
Sr2+ Ba2+ Cu2+
Al3+ Fe3+
(b) After the addition of HCl, the above sample is centrifuged and decanted. Which of the following cations remaining in the supernatant could you separate, by causing them to precipitate, with the addition of H2SO4? (Hint: H2SO4 is a source of sulfate ions. Select all that apply.)
Ag+ K+ NH4+
Hg22+ Pb2+ Mg2+
Sr2+ Ba2+ Cu2+
Al3+ Fe3+
Answer:
a13+a13
Explanation: