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Students observed that their teacher's desk plant looked wilted on Monday morning compared to how it looked at the end of the day on Friday. Some students hypothesized that a warmer room temperature over the weekend caused the plant to wilt. Other students hypothesized that the lack of light caused the plant to wilt. Both hypotheses are valuable because they
A.) are reasonable and testable ---- (My answer)
B.) compare independent variables
C.) compare light and temperature
D.) are the only possible explanations.
Answer: A.) are reasonable and testable
A hypothesis can be defined as the supposition or assumption of scientific process that is based on limited scientific evidences and used as a starting point for further investigation. The hypothesis needs to be proved by following relevant scientific methodology.
In the given situation, both the hypothesis are correct because both warm temperature and sunlight are genuinely responsible for wilting of plant in nature. The effect of both sunlight and warm temperature can be tested separately on plant. This proves that the hypothesis are reasonable and testable.
What is the density of a substance with a mass of 45.00 g and a volume of 26.5ml?
Final answer:
The density of the substance is 1.70 g/mL.
Explanation:
The density of a substance can be calculated using the formula:
Density = Mass/Volume
In this case, the mass is given as 45.00 g and the volume is given as 26.5 mL. We can use these values to calculate the density:
Density = 45.00 g / 26.5 mL
Density = 1.70 g/mL
Therefore, the density of the substance is 1.70 g/mL.
The addition of heat to a pond causes serious problems for the aquatic plants because the increase in water temperature _______.
What are the standard conditions under which reduction potentials are measured? 1°C and 1 M reactants 25°C and 1 M reactants 25°C and 2.5 M reactants 1°C and 25 M reactants
Answer:
25°C and 1 M reactants
Explanation:
The standard conditions to measure the reduction potential as standard electrode potential is 298.15 K temperature (25°C) and 1 mol / L concentration of each reactant.
The pressure should be 1 atm for gaseous reactants (like in case of Standard hydrogen electrode where pressure of hydrogen gas is taken to be 1 atm).
A segment of DNA shows bases in this order AGT CAC GCA, complete the corresponding DNA strand: TCA GTG?
A) ACG
B) CGT
C) GCA
D) TGC
Combustion analysis of toluene, a common organic solvent, gives 8.20 mg of co2 and 1.92 mg of h2o. if the compound contains only carbon and hydrogen, what is its empirical formula?
In 1912, chemist Fritz Haber developed a process that combined nitrogen from the air with hydrogen at high temperatures and pressures to make ammonia. Specifically, the process involved combining one molecule of nitrogen gas (N2) with three molecules of hydrogen gas (H2) to get two molecules of ammonia (NH3). If you write this process in a symbol format, it looks like this:
N2 + 3H2 → 2NH3
Explain whether this is a chemical or physical change, and why. Does it involve elements, compounds, mixtures, or pure substances? Also describe how many atoms are involved before and after. What do you notice about the number of atoms?
Answer:
Chemical change
Compounds
Number of atoms of hydrogen on both side=6
Number of atoms of nitrogen on both sides=2
Number of atoms of nitrogen and hydrogen on both sides are equal.
Explanation:
We are given that a reaction
[tex]N_2+3H_2\rightarrow 2NH_3[/tex]
It is chemical change because there is chemical reaction occurring .In physical change, no chemical reaction takes place.
It involved compound because compound consist of two or more than two atoms of same or different elements . In compound , the atoms are bonded together by chemical bond.
Nitrogen is a compound because two nitrogen atoms are bonded together to form a molecule of nitrogen.Similarly , in hydrogen molecules, two hydrogen atom are bonded together to form one hydrogen molecule.
In ammonia, 3 hydrogen and 1 nitrogen atom are bonded together to form ammonia.
On LHS
Number of atoms of hydrogen=6
Number of nitrogen atoms=2
On RHS
Number of atoms of Hydrogen=6
Number of nitrogen atoms=2
Number of atoms of every element in reactants equals to number of atoms of every element in product.
How many oxygen atoms are in 6.90 g of Al2(SO4)3? Express your answer using scientific notation with two decimal places.
Answer:
There are 1.44 x 10^23 atoms of oxigen in 6.90 grs of Al2(SO4)3.
Explanation:
To solve this problem you have to find:
1) The molecular mass of Al2(SO4)3;
2) Estimates the percentage of oxigen and express it in terms of its moles.
3) Calculate the number of atoms using Avogadro´s Number.
1) Molecular mass Al2(SO4)3= 2x26,98 + 3x31.06 + 12x16 =339.14 grs/mol.
2) If in the molecular mass of the compound there are 192 grs/mol (12x16) of oxigen, in 6.90 g will be:
192 grs/mol Oxigen ------------- 339.14 grs/mol Al2(SO4)3
x= 3.90 grs/mol-------------------- 6.90 grs/mol Al2(SO4)3
Then if one mol of oxigen has a mass of 16 grs, 3.90 grs represents....
1 mol oxigen ------------- 16 grs of oxigen
x= 0.24 moles------------ 3.90 grs of oxigen
3) There are 6,022 x 10^23 (Avogrado´s number) atoms of oxigen in a mol of oxigen, so in 0.24 moles will be
1 mol oxigen ---------------- 6,022 x 10^23 atoms of oxigen
0.24 moles oxigen ------- x = 1.44 x 10^23 atoms of oxigen.
Summarizing there are 1.44 x 10^23 atoms of oxigen in 6.90 grs of Al2(SO4)3.
Match the following bones with their locations on the body.
carpals
clavicle
cranium
femur
fibula
humerus
ilium
metacarpals
metatarsals
patella
choices are
arm
head
leg
chest
hand
foot
hip
If 83.0 ml of 0.150 m hcl(aq) is needed to neutralize all the nh3(g) from a 2.25-g sample of organic material, calculate the mass percentage of nitrogen in the sample.
Chemistry is the science of materials, their composition and structure and the changes they undergo, we study chemistry because
Answer:
To get a better understanding of all materials we come on contact with and how they affect and help us !
Explanation:
What type of combustion fuels produces the greenhouse gas carbon dioxide?
Write the ions present in solution of k2co3. express your answers as chemical formulas separated by a comma. identify all of the phases in your answers.
Answer : The ions present in the solution of [tex]K_2CO_3[/tex] are [tex]K^+[/tex] and [tex]CO^{2-}_3[/tex] in aqueous state.
Explanation :
When [tex]K_2CO_3[/tex] is in aqueous solution then they dissociates into their ions.
The reaction in aqueous medium is,
[tex]K_2CO_3(aq)\rightarrow 2K^+(aq)+CO^{2-}_3(aq)[/tex]
The charge on potassium ion is +1 and on carbonate ion is -2. To neutralize the charge on carbonate ion, two potassium ion must be used.
Therefore, the ions present in solution of [tex]K_2CO_3[/tex] are [tex]K^+[/tex] and [tex]CO^{2-}_3[tex] in aqueous state.
[tex]\boxed{{{\text{K}}^ + },\;{\text{CO}}_3^{2 - }}[/tex] are the ions present in the solution of [tex]{{\text{K}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}[/tex] . Both ions are in the aqueous phase.
Further Explanation:
Chemical bond:
The attraction between atoms, molecules or ions which results in the formation of chemical compounds is known as a chemical bond. It is formed either due to electrostatic forces or by the sharing of electrons. There are many strong bonds such as ionic bonds, covalent bonds, and metallic bonds while some weak bonds like dipole-dipole interactions, London dispersion forces, and hydrogen bonding.
Ionic compound:
Ionic compounds are the compounds that are formed from the ions of the respective species. Ions are the species that are formed either due to loss or gain of electrons. A neutral atom forms cation by the loss of electrons and anion by the gain of electrons.
Following are some of the properties of ionic compounds:
1. These are hard solids.
2. High melting and boiling points.
3. Good conductors of heat and electricity.
4. High enthalpy of fusion.
For example, [tex]{\text{MgC}}{{\text{l}}_2}[/tex] is an ionic compound formed from one [tex]{\text{M}}{{\text{g}}^{2 + }}[/tex] and two [tex]{\text{C}}{{\text{l}}^ - }[/tex] ions. Its dissociation occurs as follows:
[tex]{\text{MgC}}{{\text{l}}_2}\rightleftharpoons {\text{M}}{{\text{g}}^{2+}}+{\text{2C}}{{\text{l}}^ - }[/tex]
[tex]{{\mathbf{K}}_{\mathbf{2}}}{\mathbf{C}}{{\mathbf{O}}_{\mathbf{3}}}[/tex] is an ionic compound that consists of two [tex]{{\mathbf{K}}^{\mathbf{ + }}}[/tex] ions and one [tex]{\mathbf{CO}}_{\mathbf{3}}^{{\mathbf{2 - }}}[/tex] ion. Therefore it dissociates to form two [tex]{{\text{K}}^ + }[/tex] ions and one [tex]{\text{CO}}_3^{2 - }[/tex] ion. The reaction for dissociation of [tex]{{\mathbf{K}}_{\mathbf{2}}}{\mathbf{C}}{{\mathbf{O}}_{\mathbf{3}}}[/tex] is,
[tex]{{\text{K}}_2}{\text{C}}{{\text{O}}_3}\left({aq}\right)\to2{{\text{K}}^ + }\left( {aq} \right)+{\text{CO}}_3^{2 - }\left({aq}\right)[/tex]
So the ions present in [tex]{{\text{K}}_2}{\text{C}}{{\text{O}}_3}[/tex] solution are two [tex]{{\text{K}}^ + }[/tex] and one [tex]{\text{CO}}_3^{2 - }[/tex] ions. Both the ions are present in the aqueous phase.
Learn more:
1. Identification of ionic bonding: https://brainly.com/question/1603987
2. Oxidation and reduction reaction: https://brainly.com/question/2973661
Answer details:
Grade: High School
Subject: Chemistry
Chapter: Ionic and covalent compounds
Keywords: K2CO3, K+, CO32-, ionic compound, ions, one, two, dissociation, reaction, ions, cation, anion, electrons, chemical bond, attraction, properties, aqueous phase.
How many grams of salt are in 1 kilogram of seawater with average salinity? quizzlet?
Mendeleev periodic table was a useful tool because it enables scientists to
Answer:
Mendeleev's periodic table was a useful tool because it enables scientists to predict properties of unknown elements.
Explanation:
Bacillus megaterium is a mesophile that forms endospores. considering endospores are resistant to high heat, at what temperature will bacillus megaterium survive for experiment 17a if endospores are present?
Answer:
B
Explanation:
A 4.236 g sample of a hydrocarbon is combusted to give 3.810 g of h2o and 13.96 g of co2. what is the empirical formula of the compound?
A laboratory instructor gives a sample of amino acid powder to each of four students, i, ii, iii, and iv, and they weigh the samples. the true value is 8.72 g. their results for three trials are student i: 8.72g, 8.74g, 8.70g student ii: 8.56g, 8.77g, 8.83g student iii: 8.50g, 8.48g, 8.51g student iv: 8.41g, 8.72g 8.55g which set of data is both most accurate and most precise?
Answer:
student 4 for jlabs
Explanation:
The existence of discrete (quantized) energy levels in an atom may be inferred from
Final answer:
The existence of discrete energy levels in an atom can be inferred from the characteristic emission and absorption spectra unique to each element, which result from the quantized energy levels of electrons.
Explanation:
The existence of discrete (quantized) energy levels in an atom may be inferred from the emission and absorption spectra that have been known for over a century to be discrete or quantized. These spectra are unique to each element and are due to the quantized energy levels of electrons in atoms. When an electron jumps from one energy level to another, it must absorb or emit a photon with energy equal to the difference between these two energy levels; this creates specific lines in an atom's spectra. This phenomenon confirmed the idea that electrons occupy discrete orbits around the nucleus, a concept that is foundational for quantum mechanics and was part of what led to Bohr's Nobel Prize-winning work.
What would you need to do to calculate the molality of 10 mol of nacl in 200 mol of water?
The conversion of 200 mol of water to kilograms of water is needed to calculate the molality of 10 mol of NaCl in 200 mol of water. Thus, the correct option is A.
What is Molality?Molality is the measure of concentration of a solution. It is the number of moles of solute which are present in a solution that is corresponding to about 1 kg or 1000 g of solvent solution. This amount contrasts with the definition of molarity which is based on the volume of solution. A commonly used unit for molality in chemistry is mol/kg of the solvent molecule.
The formula for calculation of Molality is:
m = mol/ kg
where, m = molality of solution,
mol = number of moles of solute,
kg = kilogram of solvent
The conversion of 200 mol of water to kilograms of water is necessary for the calculation of molality of the solution.
Here, Solute (mol) = 10 mol NaCl
Solvent (Kg) = 200 mol water (Convert to kilograms of water).
Therefore, the correct option is A.
Learn more about Molality here:
https://brainly.com/question/26921570
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Your question is incomplete, most probably the complete question is:
What would you need to do to calculate the molality of 10 mol of NaCl in 200
mol of water?
A. Convert the 200 mol of water to kilograms of water.
B. Convert the 200 mol of water to liters of water.
C. Convert the 10 mol of NaCl to grams of NaCl.
D. Convert the 10 mol of NaCl to kilograms of NaCl.
What is the pressure of a gas at stp
Final answer:
The pressure of a gas at standard temperature and pressure (STP) is typically stated as 1 atm (101.325 kPa), although the IUPAC defines it as 100 kPa. STP is used to consistently compare properties of gases and the standard molar volume of an ideal gas at these conditions is about 22.4 L.
Explanation:
The pressure of a gas at standard temperature and pressure (STP) is defined as 1 atmosphere (atm). However, it's important to note that there are different definitions of STP. The most commonly used definition for STP is a temperature of 0°C (273.15 K) and a pressure of 1 atm (101.325 kPa).
But, according to the International Union of Pure and Applied Chemistry (IUPAC), STP is defined as a temperature of 0°C (273.15 K) and a pressure of 100 kPa (0.986 atm).
For simplicity and to stay consistent with older conventions, 1 atm is often still used as the standard pressure when discussing STP in many contexts.
STP conditions for comparisons include the pressure of 1 atm and temperature of 0°C (273.15 K).Scientists use STP as a reference to compare gas properties.The molar volume of an ideal gas at STP is approximately 22.4 liters.If we know that 10.0 cm3 of ice has a mass of 9.19 g what is the density of ice
What is the primary difference between a hypothesis and a theory?
A theory is supported by more data and observations than a hypothesis is.
A hypothesis is falsifiable, but a theory has been proven to be correct.
A theory is a prediction, but a hypothesis is an explanation.
A hypothesis is more reliable than a theory.
What is most plastic made of? (more than one)
inorganic compounds
organic compounds
petroleum or coal materials
carbon containing compounds
synthetic materials
Answer:
Plastics are synthetic organic compounds
Explanation:
What phrase from the Preamble justifies a law like the Affordable Care Act?
How do the number of electrons in an atom's highest energy level affect its reactivity?
O, li, c which electrons experience the greatest effective nuclear charge? express your answer as a chemical formula.
The compound ammonium sulfide is a strong electrolyte. write the reaction when ammonium sulfide is put into water:
Final answer:
When ammonium sulfide ((NH4)2S) dissolves in water, it dissociates fully into two ammonium ions (NH4+) and one sulfide ion (S2-), showcasing its behavior as a strong electrolyte.
Explanation:
The question relates to ammonium sulfide, a strong electrolyte, dissolving in water. When ammonium sulfide ((NH4)2S) is put into water, it dissociates into its ions because it is a strong electrolyte. Hence, the reaction is as follows:
(NH4)2S(s) + H2O(l) → 2NH4+(aq) + S2-(aq)
This reaction clearly shows ammonium ions (NH4+) and sulfide ions (S2-) being released into the solution. Two ammonium ions are needed to balance the charge on a single sulfide ion, reflecting the original stoichiometry of ammonium sulfide.
10,300 milliliters is the same as: cm3 and L
For this case what you should do is keep in mind the following conversions:
[tex] 1 milliliter = 1 cm ^ 3 [/tex]
[tex] 1000 milliliters = 1 L [/tex]
Therefore, by applying the conversions we have:
For cubic centimeters:
[tex] (10,300mL) (1\frac{cm^3}{mL}) = 10,300cm ^ 3 [/tex]
For liters:
[tex] (10,300mL) (\frac{1}{1000}\frac{L}{mL}) = 10.3 L [/tex]
Answer:
10,300 milliliters is the same as:
[tex]10,300cm ^ 3[/tex]
[tex]10.3 L[/tex]
How is the atomic mass of an element calculated
The atomic mass of an element is calculated by taking the weighted average of the mass numbers of all its naturally occurring isotopes, calculated by the sum of the protons and neutrons in an atom.
The atomic mass of an element is primarily the total mass of its protons and neutrons. Electrons have a negligible mass and thus are not typically included in the atomic mass calculation. To calculate the atomic mass of an element, you first need to know its mass number, which is the sum of the number of protons and neutrons.
The number of protons is the element's atomic number, and it defines the type of element. For example, carbon (C) has an atomic number of 6, hence it has 6 protons. Carbon's most common isotope has 6 neutrons, therefore, its mass number is 12.
However, because elements can have multiple isotopes with different numbers of neutrons, the atomic mass listed on the periodic table is a weighted average of the mass numbers of all the naturally occurring isotopes of an element. For instance, chlorine (Cl) has an atomic mass of 35.45 because it mainly exists as isotopes with mass numbers of 35 (17 protons and 18 neutrons) and 37 (17 protons and 20 neutrons).