Explanation: The hypothesis is a prediction, but it involves more than a guess. Most of the time, the hypothesis begins with a question which is then explored through background research. It is only at this point that researchers begin to develop a testable hypothesis.
(Unless you are creating an exploratory study, your hypothesis should always explain what you expect to happen)
(in the image)
What Is the noble gas configuration for strontium (atomic number = 38)? Given: He (atomic number = 2) Ne (atomic number = 10) Ar (atomic number = 18) Kr (atomic number = 36) B В A [Kr 45Kr 5
Answer:
[Kr] 5s²
Explanation:
From the question given above, the following data were obtained:
Atomic number of strontium (Sr) = 38
Electronic configuration =?
Next, we shall determine the electronic configuration of the noble gas element before strontium (Sr).
The noble gas element before strontium (Sr) is krypton (Kr). Thus, the electronic configuration of krypton (Kr) is given below:
Kr (36) => 1s² 2s²2p⁶ 3s²3p⁶ 3d¹⁰ 4s²4p⁶
Finally, we shall determine the electronic configuration of strontium (Sr). This can be obtained as follow:
Kr (36) => 1s² 2s²2p⁶ 3s²3p⁶ 3d¹⁰ 4s²4p⁶
Sr (38) =>?
Sr (38) => 1s² 2s²2p⁶ 3s²3p⁶ 3d¹⁰ 4s²4p⁶ 5s²
But
Kr (36) => 1s² 2s²2p⁶ 3s²3p⁶ 3d¹⁰ 4s²4p⁶
Therefore,
Sr (38) => [Kr] 5s²
If position vector r=bt²i + ct³j, where c are positive constants, when does the velocity vector make an angle of 45° with the x and y axes?
We want to find the value of t such that the velocity vector makes an angle of 45° with both axes.
We found that:
t = (2/3)*(b/c)
The velocity vector makes an angle of 45° with the x and y axes.
We know that the position vector is:
r = r=b*t²i + c*t³j
Remember that the versor "i" corresponds to the x-component, and the versor "j" corresponds to the y-component, then:
r = r=b*t²i + c*t³j = (b*t², c*t³)
The velocity vector is the vector that we get when we differentiate the position one, remember that if:
f(x) = a*x^n
then
f'(x) = n*a*x^(n - 1)
Using this, we can find that the velocity vector is:
v = (2*b*t, 3*c*t²)
Now we want to know, when does the velocity vector make an angle of 45° with the x and y axes.
Let's think of the vector as the hypotenuse of a triangle rectangle, where the x-component is the adjacent cathetus, and the y-component is the opposite cathetus. (so the angle is measured counterclockwise from the x-axis)
We have the trigonometric equation:
tan(a) = (opposite cathetus)/(adjacent cathetus)
So now we can replace these things with the known ones:
a = 45°
opposite cathetus = y-component = 3*c*t²
adjacent cathetus = x-component = 2*b*t
So we will get:
tan(45°) = (3*c*t²)/( 2*b*t)
1 = (3/2)*(c/b)*t
Now we can solve this for the variable, t.
1*(2/3)*(b/c) = t
t = (2/3)*(b/c)
We can conclude that at the time:
t = (2/3)*(b/c)
The velocity vector makes an angle of 45° with the x and y axes.
You can read more about vectors in:
https://brainly.com/question/10841907
calculate the pH of 0.01moldm-3 of trioxonitrate (v) acid
Answer:
pH = 2
Explanation:
Trioxonitrate (v) acid is also known as nitric acid (HNO₃) and is one of the strong acid set which when dissolved in water, ionizes 100%. That is,
0.01M HNO₃ => 0.01M H⁺ + 0.01M NO₃⁻ => pH = -log[H⁺] = -log(0.01) = -(-2) = 2
For the following reaction, 5.29 grams of water are mixed with excess diphosphorus pentoxide. The reaction yields 13.3 grams of phosphoric acid . diphosphorus pentoxide(s) + water(l) phosphoric acid(aq). What is the theoretical yield of phosphoric acid?
Answer:
19.2 g
Explanation:
Step 1: Write the balanced equation
P₂O₅(s) + 3 H₂O(l) ⇒ 2 H₃PO₄
Step 2: Calculate the moles corresponding to 5.29 g of H₂O
The molar mass of H₂O is 18.02 g/mol.
5.29 g × 1 mol/18.02 g = 0.294 mol
Step 3: Calculate the theoretical yield of phosphoric acid, in moles
The molar ratio of H₂O to H₃PO₄ is 3:2. The theoretical yield of H₃PO₄ is 2/3 × 0.294 mol = 0.196 mol
Step 4: Calculate the mass corresponding to 0.196 moles of H₃PO₄
The molar mass of H₃PO₄ is 97.99 g/mol.
0.196 mol × 97.99 g/mol = 19.2 g
oxidation number of Ni in Ni(CO)4 is
Answer:
0
Explanation:
answer from gauth math
Balance the following equations Ag (s) + H₂ S(g) + 0₂ (g) → Ag₂ S(₅) + H₂0
Answer:
2Ag(s) + 2H²S(g) + O2(g) ➡️ Ag2S(s) + 2H2O(g)
Explanation:
Sorry for my typo. but you understand
A sample of oxygen gas at a pressure of 1.19 atm and a temperature of 24.4 °C, occupies a volume of 18.7 liters. If the gas is allowed to expand at constant temperature to a volume of 29.4 liters, the pressure of the gas sample will be ______ atm.
Answer:
[tex]\boxed {\boxed {\sf 0.757 \ atm}}[/tex]
Explanation:
We are asked to find the pressure of a gas given a change in volume. Since the temperature remains constant, we are only concerned with volume and pressure. We will use Boyle's Law, which states the volume is inversely proportional to the pressure. The formula for this law is:
[tex]P_1V_1= P_2V_2[/tex]
Initially, the oxygen gas occupies a volume of 18.7 liters at a pressure of 1.19 atmospheres.
[tex]1.19 \ atm * 18.7 \ L = P_2V_2[/tex]
The gas expands to a volume of 29.4 liters, but the pressure is unknown.
[tex]1.19 \ atm * 18.7 \ L = P_2 * 29.4 \ L[/tex]
We are solving for the new pressure, so we must isolate the variable [tex]P_2[/tex]. It is being multiplied by 29.4 liters. The inverse operation of multiplication is division. Divide both sides of the equation by 29.4 L.
[tex]\frac {1.19 \ atm * 18.7 \ L}{29.4 \ L} =\frac{ P_2 * 29.4 \ L}{29.4 \ L}[/tex]
[tex]\frac {1.19 \ atm * 18.7 \ L}{29.4 \ L} =P_2[/tex]
The units of liters cancel.
[tex]\frac {1.19 \ atm * 18.7 }{29.4 } =P_2[/tex]
[tex]\frac {22.253}{29.4 } \ atm = P_2[/tex]
[tex]0.7569047619 \ atm =P_2[/tex]
The original measurements all have 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place. The 9 in the ten-thousandth place to the right of this place tells us to round the 6 up to a 7.
[tex]0.757 \ atm \approx P_2[/tex]
The pressure of the gas sample is approximately 0.757 atmospheres.
According to Boyle's law, for a given mass of ideal gas, pressure of gas is inversely proportional to the volume of gas, Provided the Temprature remains constant.
P₁ = 1.19 atmP₂ = ?V₁ = 18.7 LV₂ = 29.4 LT = constant = 24.4° C = Isothermal process[tex]\implies \sf P_1 V_1 = P_2 V_2 \\ [/tex]
[tex]\implies \sf 1.19 \times 18. 7= P_2 \times 29.4 \\[/tex]
[tex]\implies \sf 22.253= P_2 \times 29.4 \\[/tex]
[tex]\implies \sf P_2 = \dfrac{22.253}{29.4} \\[/tex]
[tex]\implies \underline{ \red{\boxed{ \bf P_2 \approx0.756 \: atm }}} \\[/tex]
what is the mass of cerrusite would contain 35g of lead?
Answer:
i believe its 42
Explanation:
How does a smoke detector utilize radiation?
A. Beta radiation creates a stead stream of electrons. When the stream is broken by smoke particles, it sets off the alarm.
B. Alpha radiation ionizes the air. When smoke interacts with the ionized particles it causes the alarm to sound.
C. Gamma radiation creates a stead stream of electrons. When the stream is broken by smoke particles, it sets off the alarm.
D. Beta radiation ionizes the air. When smoke interacts with the ionized particles it causes the alarm to sound.
What is the molarity of a solution that contains 17g of NH₃ in 0.50L of solution?
Please explain as well!
Explanation:
Because molarity is mol/L, we'll have to convert 17g to mol.
After obtaining the mol, we'll divide that by the volume to obtain Molarity.
[tex]\\ \sf\longmapsto NH_3[/tex]
[tex]\\ \sf\longmapsto 14u+3(1u)[/tex]
[tex]\\ \sf\longmapsto 14u+3u[/tex]
[tex]\\ \sf\longmapsto 17u[/tex]
[tex]\\ \sf\longmapsto 17g/mol[/tex]
Moles of Ammonia:-
[tex]\boxed{\sf No\:of\:moles =\dfrac{Given\:mass}{Molar\:mass}}[/tex]
[tex]\\ \sf\longmapsto No\:of\:moles=\dfrac{17}{17}[/tex]
[tex]\\ \sf\longmapsto No\;of\:moles=1mol[/tex]
Volume of solution=0.50LWe know
[tex]\boxed{\sf Molarity=\dfrac{Moles\:of\:solute}{Volume\:of\: Solution\:in\:L}}[/tex]
[tex]\\ \sf\longmapsto Molarity=\dfrac{1}{0.50}[/tex]
[tex]\\ \sf\longmapsto Molarity=2M[/tex]
Which of the following statements is/are correct? 1. There are 5 orbitals in
the d subshell. 2. The d orbitals can accommodate 14 electrons. 3. The first
shell contains s and p orbitals. 4. The s orbital can accommodate 2 electrons.
A. 1 and 4
B. 2 and 3
C. 3 and 4
D. 2 and 4
number is equal to 6022 x 10^23
Answer:
The Avogadro's number
Explanation:
the number is 6.02214x10 to the 23 power
Please help with all 3 parts!
Answer:
1:Part A.
[tex]\bold{42.2 g C_{12}H_{22}O_{11} \:in \:528 g H₂O}[/tex]
Mass Percent=[tex]\bold{\frac{Mass\: of \:Solute}{Mass\: of \:Solution}×100\%}[/tex]
=[tex]\frac{42.2}{528}*100\%=\bold{\underline{7.99\: or \:8\%}}[/tex]
Part B.
[tex]\bold{198\:m g\: C_{6}H_{12}O_{6} \:in\:4.71 g\: H₂O}[/tex]
mass of solute: 198mg
mass of solvent :4.71g=4710g
Mass Percent=[tex]\bold{\frac{Mass\: of \:Solute}{Mass\: of \:Solution}×100\%}[/tex]
=[tex]\frac{198}{4710}*100\%=\bold{\underline{4.20\%}} [/tex]
Part C.
[tex]\bold{8.85 g NaCl \:in \:190 g\: H₂O}[/tex]
Mass Percent=[tex]\bold{\frac{Mass\: of \:Solute}{Mass\: of \:Solution}×100\%}[/tex]
=[tex]\frac{8.85}{190}*100\%=\bold{\underline{4.66\%}}[/tex]
Answer:
It will help you !!!!!!!!!!
How many grams of sodium chloride are contained in 250.0 g of a 15% NaCl solution?
Please explain and show work.
Given concentration of NaCl=15%
Means ,
In every 100g of Solution 15g of NaCl is present .
Now
Given mass=250gSo ,
[tex]\\ \Large\sf\longmapsto 250\times 15\%[/tex]
[tex]\\ \Large\sf\longmapsto 250\times \dfrac{15}{100}[/tex]
[tex]\\ \Large\sf\longmapsto 37.5g[/tex]
37.5g of NaCl present in 250g of solution.
Answer:
Given concentration of NaCl=15%
Means ,
In every 100g of Solution 15g of NaCl is present .
Now
Given mass=250g
So ,
➡250 × 15%
➡250×15/100
➡37.5g
37.5g of NaCl present in 250g of solution.
· Acids are not safe to be used, but our stomach secretes hydrochloric acid. What would happen if the stomach does not carry out this task? Mark them brainlist
90
1
39
is the
In the following decay equation,
90
Sy →
38
et
90
39
-1
A. alpha particle
B. parent element
C. daughter element
D. beta particle
Answer:
D. beta particle
Explanation:
Number of protons increases from 38 to 39 indicating beta decay (only one proton up from parent isotope to daughter isotope) Also atomic mass (on top of an isotope), 90 stays the same as beta particle is very small.
12.39 HBr can be added to alkenes in either the absence or presence of peroxides (producing either the Markovnikov or the anti-Markovnikov addition product). What intermediates leading to the formation of the major product are observed when 1-butene is treated with 1) HBr or 2) HBr/peroxides
Answer:
See explanation and image attached
Explanation:
The reaction of HBr with 1-butene is an addition reaction. The HBr adds across the double bond to yield a saturated halogenoalkane.
In the absence of peroxides, the reaction proceeds in accordance with Markovnikov rule which states that;''the negative part of the addendum, is attached to the carbon atom with the least number of hydrogen atoms attached.'' This occurs in the first reaction shown in the image.
In the presence of peroxides, the reaction proceeds in an anti-Markovnikov manner to yield the product shown in the second reaction.
A student isolated an unknown organic compound through extraction. The student measures the melting point and fins it to be 115-122 C. The student looks through the list of possible strucures and decides the comound is most likely 2-napthol. Do you believe this choice is correct?
C2H5MgBr + PCl3 ra chất gì
Answer:
C2H5P
is the right answer
The first step of electrophilic aromatic substitution involves the formation of the arenium ion intermediate.
a. True
b. Fasle
Answer:
True
Explanation:
Aromatic compounds undergo substitution rather than addition reactions because the aromatic structure is maintained.
Electrophilic aromatic substitution begins with attack of the electrophile on the aromatic ring to yield a delocalized intermediate called the arenium intermediate. Loss of hydrogen from this intermediate yields the final product.
Nicotine is a toxic substance present in tobacco leaves. There are two lone pairs in the structure of nicotine. In general, localized lone pairs are much more reactive than delocalized lone pairs. With this information in mind, do you expect both lone pairs in nicotine to be reactive?
A. Both lone pairs are delocalized and, therefore, both are expected to have the same reactivity.
B.Lone pair in pyrrolidine ring is localized and, therefore, is expected to be more reactive.
C. Both lone pairs are localized and, therefore, both are expected to be reactive.
D. Lone pair in pyridine ring is localized and, therefore, is expected to be more reactive.
Answer:
B.Lone pair in pyrrolidine ring is localized and, therefore, is expected to be more reactive.
Explanation:
There are two nitrogen atoms bearing lone pairs of electrons in the structure of nicotine as shown in the image attached.
One nitrogen atom is found in the pyrrolidine ring. The lone pair on this nitrogen atom is localized hence it is more reactive than the lone pair of electrons found on the nitrogen atom in the pyridine ring which is delocalized a shown in the image attached to this answer.
HELP! How is the mass number of an atom calculated?
A - total number of electrons
B - total number of protons
C - protons plus neutrons
D - electrons plus neutrons
Which of the following is most likely to happen when a sound wave reflects
off a hard surface? (Assume that neither the source of the sound nor the hard
surface is moving.)
A. A change in speed
B. An echo
C. A change in pitch
D. A beat frequency
В
an echo is caused by the fact that waves can be reflected by solid surfaces, this is due to the dynamic pattern of rarefactions and air seals near the reflecting surface
The Halogen Group is also known as the?
salt formers
acid makers
Answer:
I think b acid makers
Explanation:
hope it will help you
Calculate the solubility of copper(II) hydroxide, Cu(OH)2, in g/L
Answer:
Ksp = [ Cu+² ] [ OH-] ²
molar mass Cu(oH )2 ==> M= 63.546 (1) + 16 (2) + 1 (2) = 97.546 g/mol
Ksp = [ Cu+² ] [ OH-] ²
Ksp [ cu (OH)2 ] = 2.2 × 10-²⁰
|__________|___Cu+² __|_2OH-____|
|Initial concentration(M)|___0__|_0______|
|Change in concentration(M)|_+S |__+2S__|
|Equilibrium concentration(M)|_S _|2S___|
Ksp = [ Cu+² ] [ OH-] ²
2.2 ×10-²⁰ = (S)(2S)²= 4S³
[tex]s = \sqrt[3]{ \frac{2.2 \times {10}^{ - 20} }{4} } = 1.8 \times {10}^{ - 7} [/tex]
S = 1.8 × 10-⁷ M
The molar solubility of Cu(OH)2 is 1.8 × 10-⁷ M
Solubility of Cu (OH)2 =
[tex]Cu (OH)2 = \frac{1.8 \times {10}^{ - 7} mol \:Cu (OH)2 }{1L} \times \frac{97.546 \: g \: Cu (OH)2}{1 \: mol \: Cu (OH)2} \\ = 1.75428 \times 10 ^{ - 5} [/tex]
Solubility of Cu (OH)2 = 1.75428 × 10 -⁵ g/ L
I hope I helped you^_^
A piece of metal has a volume of 30.0cm3 and a mass of 252g. What is its density? what metal do you think this is?
Answer:
Explanation:
get density = D = m / V = 0.252 / 0.00003 = 8400 metal will be Cu => bronzeAn outdoor gear company develops a new type of fabric that works with electricity to warm the body without interfering with motion like heavy jackets do. Research biologists, studying life in extremely cold conditions on the polar ice caps, begin wearing the new fabric because it helps them work more comfortably, and they find it increases their productivity.
What best describes how the processes of scientific investigation and technological design are involved in this situation?
The clothing company conducted a scientific investigation to communicate results to researchers, who then used the knowledge in a technological design.
The clothing company conducted a scientific investigation to produce a product that researchers could then test while designing new technology.
The clothing company used technological design to create a product that helped aid researchers conducting a scientific investigation.
The clothing company designed a new technology that provided information researchers needed in order to continue with their scientific investigation.
Answer:
C: The clothing company used technological design to create a product that helped aid researchers conducting a scientific investigation.
Explanation:
I just did the assignment on EDGE2020 and it's 200% correct!
Also, heart and rate if you found this answer helpful!! :) (P.S It makes me feel good to know I helped someone today!!) :)
A 25.0 mL sample of 0.150 M hypochlorous acid is titrated with a 0.150 M NaOH solution. What is the pH at the equivalence point? The Kaof hypochlorous acid is 3.0x10^-8.
a) 10.20
b) 7.00
c) 6.48
d) 7.52
e) 14.52
Answer:
pH = 10.20
Explanation:
The HClO reacts with NaOH as follows:
HClO + NaOH → H2O + NaClO
Where HClO and NaOH react in a 1:1 reaction.
As the concentration of both reactions is the same and the reaction is 1:1, to reach equivalence point are required the same 25.0mL.
And the NaClO produced decreases its concentration in 2 because the volume is doubled.
The concentration of NaClO is: 0.150M / 2 = 0.075M
The equilibrium of NaClO is:
NaClO(aq) + H2O(l) ⇄ HClO(aq) + OH-(aq)
Where Kb of reaction is 1.0x10⁻¹⁴ / Ka =
1.0x10⁻¹⁴ / 3.0x10⁻⁸ = 3.33x10⁻⁷ = [HClO] [OH-] / [NaClO]
[NaClO] = 0.075M
As both HClO and OH- comes from the same equilibrium,
[HClO] = [OH-] = X
Where X is the reactoin coordinate
Replacing:
3.33x10⁻⁷ = [X] [X] / [0.075M]
2.5x10⁻⁸ = X²
X = 1.58x10⁻⁴M = [OH-]
pOH = -log [OH-]
pOH = 3.80
pH = 14 - pOH
pH = 10.20What is the formula for the compound made from mercury (II) and the nitrate ion.
Answer:
Hg(NO3)2
Explanation:
Hg occurs both as Hg(I) and Hg(II) but nitrate is -1, not -2 We NORMALLY use the smallest set of subscripts but in the case of Hg(I) compounds, most of them are dimeric. Hg2Cl2, Hg2(NO3)2, etc. Note that there also is a mercury(II) nitrate; i.e., Hg(NO3)2. Therefore, although the empirical formula for mercury(I) nitrate is HgNO3, the molecular formula is Hg2(NO3)2 anf I was always encouraged to write the molecular formula instead of the empirical formula.
Hope this helps! Feel free to shoot me any questions <3
Which of the following represents a physical change?
Answer:
» Water evaporating to gas.
» Solid subliming to gas.
» Water freezing to solid.
» Solid melting to liquid.
Explanation:
[tex]{ \underline{ \blue{ \sf{christ \:† \: alone }}}}[/tex]
