Answer:
Joan's hypothesis should make a prediction about the answer to the question. A hypothesis is just an educated guess on what you think the outcome will be on the experiment. The prediction must be testable and stated in if-then form. For example, a good hypothesis for Joan's experiment could be, I think that 1/2 cup of salt will make the water boil quicker, than water without salt.
Explanation:
Hope it helped!
Can someone please help me!!
Answer:
Less in the top
your well wisher
how many moles of nitrogen gas are produced in the reaction if we started with 6 moles of ammonium nitrate
The percent by mass of iron(III) 1 Fe2S3
is _____%
Answer:
percent=69.94%
5. Given the formula of a substance:
H Hн H
IT
C-C-C=C
1
H
H
What is the total number of shared electrons in a
molecule of this substance?
A) 22
B) 11
C) 9
D) 6
A) 22
In a single bond one pair of electrons is shared, with one electron being contributed from each of the atoms. Double bonds share two pairs of electrons and triple bonds share three pairs of electrons. Bonds sharing more than one pair of electrons are called multiple covalent bonds.In the given molecule:
There are total 7 single bonds and 2 double bonds.
As we know, In a single bond one pair of electrons is shared and double bonds share two pairs of electrons.
Thus,
Total number of shared electrons in a molecule= 7*2+2*4=14+8=22
So, total number of shared electrons in a molecule is 22.
Therefore, option A) is correct.
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You have 0.531 L of gas in a container. What is the volume in mL?
Answer:
531 mL is the volume in mL
Answer:
Hi there!
I hope you are having an outstanding day.
I believe the answer to your question is 531!
Please adress me if I am incorrect. :)
Much love,
Pandora
Explanation:
The iodide (I2) content of a commercial mineral water was measured by two methods that produced wildly different results.6 Method A found 0.23 milligrams of I2 per liter (mg/L) and method B found 0.009 mg/L. When Mn21 was added to the water, the I2 content found by method A increased each time that more Mn21 was added, but results from method B were unchanged. Which of the Terms to Understand describes what is occurring in these measure- ments? Which result is more reliable?
Answer:
Results from method B is more reliable than method A.
Explanation:
The two method that are used for the analysis produced different results. The first method that is method A gives higher value of the iodine content than the method B.
When [tex]$Mn^{2+}$[/tex] was added to water, method A showed an increased in the iodine content and it increases with the increase in the amount of [tex]$Mn^{2+}$[/tex] .
Where as in the method B, there is no change in the results. Therefore the measurements provided by the method A shows an inference of [tex]$Mn^{2+}$[/tex] ion.
The measurement of the iodine content is affected by the presence of the ion [tex]$Mn^{2+}$[/tex] in water.
Since in method B there is no change in measurement, it is independent of the presence [tex]$Mn^{2+}$[/tex] ion in water.
As higher iodine content is given by method A, so [tex]$Mn^{2+}$[/tex] ion must be present in original water that must be interfering the measurement. Hence, method B is more reliable.
Method B is more reliable as its value is not altered by external factors such as contamination.
What is water analysis?Water analysis is done to test the quality of water.
The method employed in water analysis is titrimetric analysis.
In the test iodide (I⁻) content of a commercial mineral water using the two methods, the results of the test showed different values for the iodide content.
However, since addition of Mn²⁺ to the mineral water increases the iodide content value from Method A while that of Method B remains unchanged, Method B is more reliable as its value is not altered by external factors such as contamination.
Learn more about titrimetric analysis at: https://brainly.com/question/8463543
Pls help me over here
Answer:
1 and the element is hydrogen (there is an exception for the octet rule for the element hydrogen) hope this helps
Explanation:
how many significant digits are in the number 1.0 × 10^3?
I need help ASAP plz :)
How many grams equal 4.3 x 1024 atoms of oxygen (02)?
Answer: 248.66g
Explanation:
4.3e24 / 6.23e23 = 6.9 mols O2
6.9(18.02*2)=248.66
Calculate the percent composition (out of 100) by weight of potassium in potassium carbonate decahydrate.
Answer:
12.26%
Explanation:
MM K = 39.1 g/mol
MM K2CO3 . 10H2O = 2x39.1 + 12.01 + 3 x 15.99 + 10 x 18.02= 318.38 g/mol
% by weight = (MM K/MM K2CO3.10H2O ) x 100= (39.1/318.8) x 100=12.26 %
The percent composition by weight of potassium in potassium carbonate decahydrate is 13.98%
Let's represent the chemical formula of the compound as follows;
potassium carbonate decahydrate = CH₂0KO₁₃
The molecular mass of the compound can be calculated as follows:
Molecular mass of CH₂₀KO₁₃molecular mass = 12 + 20 + 39 + (16×13) = 279 g/molmass of potassium = 39 g
Therefore,
% mass of potassium = 39 / 279 × 100
% mass of potassium = 3900 / 279
% mass of potassium = 13.9784946237
% mass of potassium = 13.98 %
learn more on percentage composition here: https://brainly.com/question/3905173
pond water with microscopic organisms inside mixture or pure substance
Answer:
it's mixture
Explanation:
since pond is composed of not only microbes and also more aqatic animals so I think pond become mixture but not pure substance am I right or not...
Help me with my homework plzy
Answer:
the second answer choice i think
Explanation:
Which example indicates that a chemical change has occurred? *
1 point
A. When two aqueous solutions are mixed, a precipitate is formed.
B. As ammonium nitrate dissolves in water causes the temperature to decrease.
C. Alcohol evaporates when left in an open container.
D. Water is added to blue copper(II) chloride solution. The resulting mixture if lighter blue in color.
Answer:
A. When two aqueous solutions are mixed, a precipitate is formed.
Explanation:
The precipitate (a solid substance that falls from the liquid) is the result of a chemical reaction taking place between the liquids.
The other three answer choices are indicative of physical changes (temperature change, phase change, color change).
When two aqueous solutions are mixed, a precipitate is formed indicates that a chemical change has occurred.
Hence, option A is correct answer.
What is Chemical change ?Chemical change are those changes in which substance changes chemical composition. These changes are permanent changes. In chemical change new substances formed and in chemical change substances can not get back into its original form. It is irreversible change.
What is Physical change ?Physical changes are those changes in which substance changes physical properties only. Properties like temperature, pressure, shape, color, size, state (solid, liquid and gas). These changes are temporary in nature. In physical change no new substances formed. It is reversible change.
Now, check all the options one by one:
Option (A): When two aqueous solutions are mixed, a precipitate is formed is a chemical change. Since precipitation indicate a chemical reaction (that is double displacement reaction).
Option (B): As ammonium nitrate dissolved in water causes the temperature to decrease is a physical change because heat energy is absorbed here and it is a endothermic reaction.
Option (C): Alcohol evaporates when left in an open container is a physical change because evaporation is a physical change as it changes the state from liquid state to gas state.
Option (D): Water is added to blue copper (II) chloride solution. The resulting mixture if lighter blue in color is a physical change as properties like change in color is physical change.
Thus, from above conclusion we can say that When two aqueous solutions are mixed, a precipitate is formed indicates that a chemical change has occurred.
Hence, option A is correct answer.
Learn more about physical and chemical change here: https://brainly.com/question/17166994
#SPJ2
help plz and will give brainly
mathdrrggeszdrsz seer r-
Answer:
130!!
Explanation:
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.
:)ᴍᴀʀᴋ ᴀꜱ ʙʀᴀɪɴʟɪꜱᴛ
If you began a reaction with the following ions in solution, what would be the net ionic equation?
Na+, PO43–, Fe2+, and NO3–
Answer:
2 PO₄³⁻(aq) + 3 Fe²⁺(aq) ⇒ Fe₃(PO₄)₂
Explanation:
Let's consider the complete ionic equation between the ions present. It includes all the ions and the insoluble compounds (Fe₃(PO₄)₂ is insoluble).
Na⁺(aq) + 2 PO₄³⁻(aq) + 3 Fe²⁺(aq) + NO₃⁻(aq) ⇒ Fe₃(PO₄)₂ + Na⁺(aq) + NO₃⁻(aq)
The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and the insoluble compounds.
2 PO₄³⁻(aq) + 3 Fe²⁺(aq) ⇒ Fe₃(PO₄)₂
The equation below illustrates the process of
Pb2+ (aq) + 11- (aq) → Pblu (s)
a) dissolution
b) precipitation
c) decomposition
Answer:
The correct answer is - b) precipitation.
Explanation:
In the given question the lead ion in an aqueous solution is mixed with the Leutium ion in an aqueous solution and forms an insoluble or solid salt. This type of reaction is referred to as precipitation reactions in chemistry.
Such reactions are helpful in determining if a particular ion is present in the solution or not.
Pb2+ (aq) + lu- (aq) → Pblu (s)
Guys please help me i will mark brainly!
Answer:
D
Explanation:
Whoever gets these 2 right gets brainliest! :)
the first one is A covalent bond.
the second one is Answer: B Decomposition
hi, if your looking for extra points (50+) and br ainiest here is ur chance, answer this question correctly plz
Hydrogen has an oxidation number of +1 in all compounds excepts when it binds with metals and has an oxidation state of -1.
Answer:
See explanation
Explanation:
In the periodic table, hydrogen is placed in group 1 for convenience. Hydrogen is not a metal, however, its common oxidation state is +1. It easily forms a univalent positive ion just like group 1 elements.
So, when hydrogen is combined with strongly electropositive metals such as sodium, lithium, etc, hydrogen accepts one electron and exhibits an oxidation state of -1 in those compounds.
Such compounds in which hydrogen is combined with strongly electropositive metals to give a binary compound is called a hydride.
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Online Content: Site 1
How did the gold rush transform Australia? (Site 1)
marking brainliest
Answer:
In 1851 gold-seekers from around the world began pouring into the colonies, changing the course of Australian history. The gold rushes greatly expanded Australia's population, boosted its economy, and led to the emergence of a new national identity.
Explanation:
Answer:
People from all over the world look for gold and in 1851 people started forming colonies to look for it which had a huge impact on the history of Australia. The gold rushes increased Australia's population which improved its economy.
What % of original U238 remains after three half lives?
1-50
2-25
3-12.5
4-6.25
Answer:
12.5
Explanation:
After three half-lives, one eighth (1/2 x 1/2 x 1/2) of the uranium-238 will remain. One-eighth equals 12.5%
thermal energy is what we call energy that come from ___ of matter
Which of these statements best supports the idea that a cell is the basic unit of a living organism?
A.
The number of cells in an organism affects the size of that organism.
B.
A tissue is composed of cells with similar structure and function.
C.
Some organisms have only one cell.
D.
All organisms are made up of one or more cells.
Answer:
The answer is D.
Explanation:
I searched it up :)
A student plans a two-step synthesis of 1-ethyl-3-nitrobenzene from benzene. The first step is nitration of benzene to give nitrobenzene, and the second step is a Friedel-Crafts alkylation using CH3CH2Cl and AlCl3. The plan is flawed because: A : When the alkyl halide interacts with AlCl3, the resulting carbocation can rearrange before it has a chance to react with the aromatic ring. B : Nitrobenzene is too deactivated (by the nitro group) to undergo a Friedel-Crafts alkylation. C : The nitro group will direct the incoming alkyl group para position, rather than to the meta position. D : A blocking group is required to achieve this synthesis.
Answer:
Nitrobenzene is too deactivated (by the nitro group) to undergo a Friedel-Crafts alkylation.
Explanation:
The benzene ring in itself does not easily undergo electrophilic substitution reaction. Some groups activate or deactivate the benzene ring towards electrophilic substitution reactions.
-NO2 ia a highly deactivating substituent therefore, Friedel-Crafts alkylation of nitrobenzene does not take place under any conditions.
This reaction scheme is therefore flawed because Nitrobenzene is too deactivated (by the nitro group) to undergo a Friedel-Crafts alkylation.
help please guys i need it
Answer:
Amplitude
Explanation:
Hope I helped :)
Use the balanced equation in the image below. How many moles of
ammonia (NH3) will be produced if 2.22 moles of nitrogen (N2) are used?
(Assume there is excess hydrogen gas.) SHOW YOUR WORK TO RECEIVE
CREDIT. *
N2 + 3H2 → 2 NH3
Since there is excess hydrogen, that means that the concentration of hydrogen is not limiting.
According to the balanced chemical equation:
every mole of N2 and every 3 moles of H2 we obtain 2 moles of NH3. Since we have the amount of N2 and excess of hydrogen, we only need to work with the amount of N2.
1 mol of N2 will produce 2 moles of NH3
so now we can get a conversation tool :
moles of N2 * (2 moles of NH3/ 1 mole of N2) = moles of NH3
(2.22 mol of N2 x 2) ÷ 1 = 4.44 mol of NH3