Answer:
Observational evidence is essential for investigating the way disease affects populations, the patterns and distribution of risk within them, and the emergence of trends in health and disease over time.
Answer:
It tests a prediction It supports the results. It asks a testable question It predicts what will happen
Explanation:
Graciella divided her grapes equally among 6 friends. If each friend received 16 grapes how many grapes did Graciella have?
Answer: She had 96 grapes.
Explanation:
Answer:
taiks
Explanation:
You want to compare the malleability of
two metals. Plan an investigation that would allow you to determine
which metal is more malleable .
The temperature and the strength of the metallic link are the two most crucial variables that can impact how malleable a metal or alloy is.
What is metal ?A metal is a substance that has a shiny look when freshly processed, polished, or shattered, and conducts electricity and heat rather effectively. Generally speaking, metals are malleable and ductile.
The amount of pressure that a metal can sustain without breaking can be used to gauge its malleability. Varied metals have different degrees of malleability because of variations in their crystal structures.
The temperature of the metal and the strength of the metallic connection are the two parameters that define how malleable a metal or metal alloy will be.
Thus, The kind of the metallic connection can have a significant impact on how easily metal atoms can rearrange themselves.
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A chemist prepares a solution of aluminum sulfate by weighing out of aluminum sulfate into a volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's aluminum sulfate solution. Be sure your answer has the correct number of significant digits.
Answer:
25.8 g/dL
Explanation:
A chemist prepares a solution of aluminum sulfate by weighing out 116.0 g of aluminum sulfate into a 450. mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in g/dL of the chemist's aluminum sulfate solution. Be sure your answer has the correct number of significant digits.
Step 1: Given data
Mass of aluminum sulfate (m): 116.0 gVolume of the solution (V): 450. mLStep 2: Convert "V" to dL
We will use the following conversion factors.
1 L = 1000 mL1 L = 10 dL450. mL × 1 L/1000 mL × 10 dL/1 L = 4.50 dL
Step 3: Calculate the concentration (C) of aluminum sulfate if g/dL
We will use the following expression.
C = m/V = 116.0 g/4.50 dL = 25.8 g/dL
Ammonium phosphate is an important ingredient in many solid fertilizers. it can be made by reacting aqueous phosphoric acid with liquid ammonia. calculate the moles of ammonium phosphate produced by the reaction of 0.085 mol of ammonia. be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.
Answer:
0.028 mole of ammonium phosphate, (NH₄)₃PO₄.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
H₃PO₄ + 3NH₃ —> (NH₄)₃PO₄
From the balanced equation above,
3 moles of NH₃ reacted to produce 1 mole of (NH₄)₃PO₄.
Finally, we shall determine the number of mole of (NH₄)₃PO₄ produced by the reaction of 0.085 mole of ammonia, NH₃. This can be obtained as follow:
From the balanced equation above,
3 moles of NH₃ reacted to produce 1 mole of (NH₄)₃PO₄.
Therefore, 0.085 mole of NH₃ will react to produce = (0.085 × 1)/3 = 0.028 mole of (NH₄)₃PO₄.
Thus, 0.028 mole of ammonium phosphate, (NH₄)₃PO₄ were obtained from the reaction.
Of the three layers of the biosphere, which one is inhabited by jellyfish?
Answer:
Hydrosphere
Explanation:
The biosphere simply refers to the zone of life found on earth. It refers to the portion of the earth inhabited by living things.
The biosphere is divided into three, namely; hydrosphere, atmosphere and lithosphere.
The atmosphere is simply the layer composed of air, the lithosphere is the solid part of the earth while the hydrosphere is the part composed of water.
Since jelly fish is an aquatic animal, it will certainly inhabit the hydrosphere. Hence the answer above.
Every morning, Jeremiah uses a blender to make a smoothie for breakfast. Which of the
following shows the energy transformation that the blender demonstrates?
А
Electrical - light
B
Chemical → mechanical
с
Mechanical → chemical
D
Electrical mechanical
Answer:
D
Explanation:
Answer:
D: Electrical -> mechanical
Explanation:
Hope this helps!
The total thermal energy of a system depends jointly on the temperature, total number of in the system _______________, and the _______________of the material. *
1. Molecules/State
2. Molecules/Heat
3. Matter/Heat
4. Atoms/State
Answer:
Molecules/State
Explanation:
We know from the kinetic molecular theory that matter is made up of molecules. These molecules are in constant motion at various velocities and energies.
The total thermal energy refers to the total kinetic energies of these particles. It depends on the temperature of the system, the energies of the molecules present in the material and the arrangement of the object's molecules (states of matter).
How many formula units are contained in 0.57 g Cao?
YOU MUST SHOW YOUR WORK FOR FULL CREDIT!
1. Jimmy picks up a 5kg box and places it on a shelf 1 meter from the ground. What is the
gravitational potential energy of the box?
Answer: 49 joules
Explanation: gravitational potential energy = mgh
m= mass kg, g= acceleration due to gravity 9.8 m/sec/sec, h= height m
=5*9.8.1 joules = 49 joules
When 70.4 g of benzamide (C7H7NO) are dissolved in 850. g of a certain mystery liquid X, the freezing point of the solution is 2.7 C lower than the freezing point of pure X. On the other hand, when 70.4 g of ammonium chloride (NH CI) are dissolved in the same mass of X, the freezing point of the solution is 9.9 °C lower than the freezing point of pure X.
Required:
Calculate the van't Hoff factor for ammonium chloride in X.
Answer:
1.62
Explanation:
From the given information:
number of moles of benzamide [tex]=\dfrac{70.4 \ g}{121.14 \ g/mol}[/tex]
= 0.58 mole
The molality = [tex]\dfrac{mass \ of \ solute (i.e. \ benzamide )}{mass \ of \ solvent }[/tex]
[tex]= \dfrac{0.58 }{0.85 }[/tex]
= 0.6837
Using the formula:
[tex]\mathbf {dT = l \times k_f \times m}[/tex]
where;
dT = freezing point = 27
l = Van't Hoff factor = 1
kf = freezing constant of the solvent
∴
2.7 °C = 1 × kf × 0.6837 m
kf = 2.7 °C/ 0.6837m
kf = 3.949 °C/m
number of moles of NH4Cl = [tex]\dfrac{70.4 \ g}{53.491 \ g /mol}[/tex]
= 1.316 mol
The molality = [tex]\dfrac{1.316 \ mol}{0.85 \ kg}[/tex]
= 1.5484
Thus;
the above kf value is used in determining the Van't Hoff factor for NH4Cl
i.e.
9.9 = l × 3.949 × 1.5484 m
[tex]l = \dfrac{9.9}{3.949 \times 1.5484 \ m}[/tex]
l = 1.62
A change of state is a(n)
process.
A. irreversible
B. reversible
Answer:
Changes of states are reversible, you can go from a solid to liquid and liquid to solid.Answer:
Reversible
Explanation:
Changes of state are physical changes in matter. Common changes of the state include melting, freezing, sublimation, deposition, condensation, and vaporization.
What is the value of 4.698 after rounding it down to 3 significant figures?
What is the maximum mass of ammonia (NH3) that can be produced from the synthesis reaction of 781 g of nitrogen and 656 g hydrogen?
HINT: You will need to write a balanced chemical equation and perform 2 calculations before you can determine the answers.
Sulfurous acid reacts with barium hydroxide.
Answer:
Ba(OH)2 + H2SO3 = BaSO3 + H2O -
Explanation:
In general, weathering tends to occur more rapidly in warm climates than in cool climates. How does this trend explain the effect of temperature on erosion rates?
Answer:
See explanation
Explanation:
Weathering refers to the breakdown of rocks to form soil. There are several agents of weathering.
In warmer regions, there are more vegetation and microorganisms and they increase the rate of biological weathering.
Since weathering leads to the formation of soil and the rate of weathering is greater in warmer climates, it also follows that as temperature increases and more soil is formed, erosion will happen faster at this higher temperature owing to the presence of more soil compared to colder climates.
There is a huge and direct effect of temperature on the rates of erosion.
The highest rate of weathering occurs in warm and wet climate because in warm and wet climatic regions, more rainfall occurs which increase the rate of weathering. Rainfall and temperature can affect the rate in which rock weathering occurs.
High temperatures and greater rainfall increase the rate of chemical weathering. Rocks in tropical regions exposed to abundant rainfall so we can conclude that hot temperatures weather much faster than similar rocks residing in cold, dry regions.
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Calculate the mass of butane needed to produce 99.0 g of carbon dioxide.
Express your answer to three significant figures and include the appropriate units.
Answer:
32.7 g
Explanation:
Step 1: Write the balanced combustion reaction
C₄H₁₀ + 6.5 O₂ ⇒ 4 CO₂ + 5 H₂O
Step 2: Calculate the moles corresponding to 99.0 g of CO₂
The molar mass of CO₂ is 44.01 g/mol.
99.0 g × 1 mol/44.01 g = 2.25 mol
Step 3: Calculate the moles of C₄H₁₀ needed to produce 2.25 moles of CO₂
The molar ratio of C₄H₁₀ to CO₂ is 1:4. The moles of C₄H₁₀ needed are 1/4 × 2.25 mol = 0.563 mol.
Step 4: Calculate the mass corresponding to 0.563 moles of C₄H₁₀
The molar mass of C₄H₁₀ is 58.12 g/mol.
0.563 mol × 58.12 g/mol = 32.7 g
Determine where each type of cleaning solution should be discarded after use. Solvent used to rinse chemicals out of a beaker ______Acid solution used to clean a crucible _________Water used to rinse detergent out of a flask ________
Answer:
Acidic solution used to clean a crucible
Explanation:
This liquid dissolves alcoholic solvents such as crucible, that is why it was selected as the ideal for cleaning.
Although it would be ideal to know in detail which chemical compound is the one you want to clean so that the cleaning technique has better effectiveness.
WASTE CONTAINER refers to the solvent used to rinse chemicals out of a beaker, and it also refers to the acid solution used to clean a crucible. Water used to rinse the detergent out of a flask refer to the SINK.
The disposal containers in a lab can be used for recycling, disposal of trash, glassware disposal box, sharp box, etc.A waste container is a container usually used to dispose of waste in a laboratory, which may be made of plastic.Moreover, a laboratory sink can be used to wash tools and/or hands without the hazard of damaging the health or the sink.In conclusion, WASTE CONTAINER refers to the solvent used to rinse chemicals out of a beaker, and it also refers to the acid solution used to clean a crucible. Water used to rinse the detergent out of a flask refer to the SINK.
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Indium has a tetragonal unit cell for which the a and c lattice parameters are 0.459 and 0.495 nm, respectively. (a) If the atomic packing factor and atomic radius are 0.693 and 0.1625 nm, respectively, determine the number of atoms in each unit cell. (b) The atomic weight of indium is 114.82 g/mol; compute its theoretical density. (a) Enter your answer for part (a) in accordance to the question statement atoms/unit cell (b) Enter your answer for part (b) in accordance to the question statement g/cm3
Answer:
A) 4 atoms/unit cell
B) 7.31 g/cm^3
Explanation:
A) Determine the number of atoms in each unit cell
attached below is the detailed solution
number of atoms per unit cell ( n ) = 4 atoms/unit cell
B) Given atomic weight of indium = 114.82 g/mol
hence the theoretical density = 7.31 g/cm^3
Attached below is a detailed solution of the question
What is wrong with the following electron configuration?
Answer:
a. without completing 2p stuff...electrons cant go to 3s. the correct configuration is
1s2, 2s2, 2p6, 3s1
b. after 4s, 3d comes not 4d. the correct configuration is 1s2, 2s2, 2p6, 3s2, 4s2, 3d6
c. after 4s, it is 3d and then 4p the correct configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6.
Hope it helps you ｡◕‿◕｡
When a precipitation reaction occurs, the ions that do not take part in the reaction are called
A.non participants
B.useless ions
C.independent variables
D.spectator ions
Answer:
D. spectator ions.
Explanation:
Hello!
In this case, when going over net ionic equations by which precipitation reactions are analyzed, we can consider the example of lead (II) nitrate with potassium iodide to yield insoluble lead (II) iodide and soluble potassium nitrate according to:
[tex]2KI(aq)+Pb(NO_3)_2(aq)\rightarrow PbI_2(s)+2KNO_3(aq)[/tex]
Whereas aqueous species remain in solution:
[tex]2K^+(aq)+2I^-(aq)+Pb^{2+}(aq)+2(NO_3)^-(aq)\rightarrow PbI_2(s)+2K^+(aq)+2(NO_3)^-(aq)[/tex]
It means that potassium and nitrate ions are spectator ions because they are not involved in the precipitation reaction, which is represented by the net ionic one:
[tex]2I^-(aq)+Pb^{2+}(aq)\rightarrow PbI_2(s)[/tex]
Thus, the answer to this question is D. spectator ions.
Best regards!
To determine the concentration of citric acid, you will need to titrate this solution with 0.100 M NaOH. You are given a 1.00 M NaOH stock solution and will need to make enough 0.100 M NaOH to perform 3 titrations. For each titration, you will use 20.0 mL of 0.100 M NaOH solution.
Calculate the total volume (in mL) of the diluted solution you will need to prepare for the 3 titrations.
Determine the minimum volume (in mL) of 1.00 M NaOH stock solution needed to prepare the 0.100 M NaOH solution.
Answer:
60.0mL of the diluted solution are needed
6.00mL of the 1.00M NaOH stock solution is the minimum volume needed to prepare the diluted solution.
Explanation:
As in each titration we need to use 20.0mL of the diluted 0.100M solution. As there are 3 titration, the volume must be:
3 * 20.0mL = 60.0mL of the diluted solution are needed
Now, to prepare a 0.100M NaOH solution from a 1.00M NaOH stock solution the dilution must be of:
1.00M / 0.100M = 10 times must be diluted the solution.
As we need at least 60.0mL, the minimum volume of the stock solution must be:
60.0mL / 10 times =
6.00mL of the 1.00M NaOH stock solution is the minimum volume needed to prepare the diluted solution.if a molecular formula is C8H12O2, what is the empirical formula
Answer:
C₄ H₆ O
Explanation:
The molecular formula of the compound is given as:
C₈ H₁₂ O₂
The molecular formula of a compound is expresses the true number of atoms within a compound.
The empirical formula gives the simplest ratio of the atoms within a compound.
Elements C H O
Number of atoms 8 12 2
Divide through by a
Common factor 8/2 12/2 2/2
4 6 1
The empirical formula therefore is C₄ H₆ O
Please help with whatever this is and go in number order
What is the mass of 1.75 moles of Ca(H2C302)2?
Explanation:
first we have to find molar mass of ca(H2c3o2)2
40+(1*2)2+(12*3)2+(16*2)2
40+4+72+64=180g/mole
m=n*Mm
m=1.75mole*180g/mole
m=315g
The gas carbon dioxide is a pure substance. Which of the following is true about carbon dioxide? (5 points)
Select one:
a. Carbon and oxygen are chemically bonded in it.
b. Carbon and oxygen retain their original identity in it.
c. It can be separated into carbon and oxygen using physical methods.
d. The proportion of carbon and oxygen is different in different samples of the gas.
Answer:
Carbon and oxygen are chemically bonded in it.
Explanation:
The other answer choices do not apply for compounds, but rather for mixtures instead.
helpppp nowww plssss nowww!!
A compound is made of 6.00 grams of oxygen, 7.00 grams of nitrogen, and 20.00grams of hydrogen. Find the percent composition of the compound.
A O-18.18%, N-21.21%, H-60.60%
B O-11.18%, N-22.21%, H-69.60%
C O-20%, N-30%, H-50%
D O-60.60%, N-21.21%, H-18.18%
The percent composition of the compound.
A O-18.18%, N-21.21%, H-60.60%
Further explanationGiven
6.00 grams of oxygen,
7.00 grams of nitrogen,
20.00 grams of hydrogen.
Required
The percent composition
Solution
Total mass :
= mass of O + mass of N + mass of H
= 6 + 7 + 20
= 33 g
% O = 6/33 x 100%= 18.18%
% N = 7/33 x 100%=21.21%
% H = 20/33 x 100% = 60.6 %
The heat of vaporization of water at the normal boiling point, 373.2 K, is 40.66 kJ/mol. The molar heat capacity of liquid water is 75.37 J K-1 mol-1 and that of gaseous water is 36.4 J K-1 mol-1. Assume that these values are independent of temperature. What is the heat of vaporization of water at 300.2 K?
Answer:
[tex]\Delta _{vap}H(300.2K)=43,658\frac{J}{mol}=43.66\frac{kJ}{mol}[/tex]
Explanation:
Hello!
In this case, according to the Kirchhoff's law for the enthalpy change, it is possible to compute the heat of vaporization at 300.2 K by considering the following thermodynamic route:
[tex]\Delta _{vap}H(300.2K)=Cp_{liq}(T_b-T\°)+\Delta _{vap}H\°+Cp_{vap}(T-T_B)[/tex]
Whereas the first term stands for the effect of taking the liquid from 298.15 K to 373.15 K, the second term stands for the standard enthalpy of vaporization and the last term that of the vapor from the boiling point to 300.2 K; thus we plug in to obtain:
[tex]\Delta _{vap}H(300.2K)=75.37\frac{J}{mol*K} (373.2K-298.15K)+40,660\frac{J}{mol} +36.4\frac{J}{mol*K}(300.2K-373.2K)\\\\\Delta _{vap}H(300.2K)=43,658\frac{J}{mol}=43.66\frac{kJ}{mol}[/tex]
Best regards!
How can the IR spectrum be used to show that there is not starting material left and the products are alcohols
Answer:
hello your question is incomplete attached below is the complete question
answer :
Absence of c = c = C-H of the peak and the presence of -O-H and C-O peak shows that there is presence of Alcohols as products and it also shows that there is no starting material left
Explanation:
To provide that there is no starting material left and products are alcohols using the IR spectrum we will apply hydroboration oxidation
Absence of c = c = C-H of the peak and the presence of -O-H and C-O peak shows that there is presence of Alcohols as products and it also shows that there is no starting material left
attached below is the detailed solution
How many molecules are in 15 moles of CO2?
There are 90.345 x 10^23 molecules in 15 moles of CO2.
What is Avogadro's number?Avogadro's number is the number of units, atoms or molecules in one mole of a substance which is equals to 6.02214076 × 1023. This number is also known as the Avogadro constant.
This means that one mole of a substance is equals to 6.02214076 × 1023 atoms, ions or molecules then 15 moles is equals to 90.345 x 10^23 molecules so we can conclude that there are 90.345 x 10^23 molecules are in 15 moles of CO2.
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