Answer:
279.225g
Explanation:
If I add 25mL of water to 125 mL of 0.25 M NaOH solution, what will the molarity of the diluted solution be?
Answer:
0.208333 M
Explanation:
M2=M1V1/V2=(0.25 M)(125mL)/(125mL+25 mL)= 0.208333 M
A piece of charcoal is found to contain
30% of the carbon 14 that it originally
had. When did the tree die from which the
charcoal came? use 5600 years as the
half-life of carbon 14.
A) 9709.46
B) 9708.33
C) 9708.34
D) 9709.45
Answer: The tree died 9709.46 years before.
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant = 100
a - x = amount left after decay process = [tex]\frac{30}{100}\times 100=30[/tex]
a) to find rate constant
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{5600years}=1.24\times 10^{-4}years^{-1}[/tex]
b) to know the age
[tex]t=\frac{2.303}{1.24\times 10^{-4}}\log\frac{100}{30}[/tex]
[tex]t=9709.46years[/tex]
The tree died 9709.46 years before.
The compound calcium carbonate contains the calcium ion (Ca2+) and the polyatomic carbonate ion (CO32-). Explain why calcium carbonate is considered to be an ionic compound when it contains both ionic and covalent bonds.
Answer:
Because of the electronegativity difference C-O (covalent) and Ca-O (ionic) bonds have.
Explanation:
Hello there!
In this case, in order to understand the polarity of this compound, calcium carbonate, it firstly necessary that it is comes from the definition of electronegativity, as a property defining the capacity to attract electrons from another atom; thus, since the electronegativities of calcium, carbon an oxygen are 1.0, 2.55 and 3.44, it is possible to realize this compound has O-Ca and O-C bonds according to its Lewis dot structure. In such a way, we calculate the difference electronegativity for these two bonds:
[tex]\Delta E_{O-Ca}=3.44-1.0 = 2.44\\\\\Delta E_{O-C}=3.44-2.55=0.89[/tex]
Thus, since 2.44 accounts for an ionic bond and 0.89 for a covalent one, we bear out the given statement in the question.
Which element, when combined with phosphorus, would form an ionic compound?
A) Carbon.
B)Oxygen.
C)Magnesium.
D)Boron.
There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, the correct option is option C.
What is chemical Compound?Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
An ionic compound is a metal and nonmetal combined compound. Ionic compound are very hard. They have high melting and boiling point because of strong ion bond.
Since phosphorus is a nonmetal, we need a metal. Out of given option the only element that is metal is Magnesium while others are non metal.
Therefore, the correct option is option C.
To learn more about chemical compound, here:
https://brainly.com/question/26487468
#SPJ2
explain how of hope's apparatus can be used to demonstrate anomalous behaviour and water class 10
Answer:
The anomalous expansion of water refers to the fact that water, unlike most substances, expands when it freezes. The density of water increases as temperature decreases, but reaches a maximum at 4 degrees C then begins to expand. The significance of this is that ice is less dense than water so it floats in water.
This is of major biological importance. Lakes, ponds and streams freeze from the top down instead of from the bottom.
Explain how the hypothalamus and certain endocrine glands work together to maintain the following conditions in the body. Specify the endocrine glands involve and the hormones it releases.
Answer:
Nerve cells in the hypothalamus make chemicals that control the release of hormones secreted from the pituitary gland. The hypothalamus gathers information sensed by the brain (such as the surrounding temperature, light exposure, and feelings) and sends it to the pituitary.
Explanation:
What kind of elements are on the left side of the zig-zag line on the periodic table?
Answer:
Metals are found to the left of the zigzag line on the periodic table. B. Nonmetals Nonmetals are found to the right of the zigzag line on the periodic table.
Explanation:
What is the pOH of a solution that has an H+=7.7x10^-7 M
Answer:
Explanation:
Step 1
The question is based on the concept of PH and pOH calculations.
pH is defined as negative logarithmic of hydronium Ion concentration.
while pOH is defined as negative logarithmic of hydroxide ion concentration of the solution.
Step 2
[H+] = 7.7*10-7 M
pH = -log[H+]
= -log ( 7.7*10-7 )
= 6.12
Step 3
pOH = 14 - pH
= 14 - 6.11
= 7.89
If you want to make 174 grams of NiFz, how many moles of HF will you need, using
the following balanced chemical equation? Ni + 2 HF - NiF2 + H2
Answer:
3.6mol
Explanation:
The balanced chemical equation of this reaction is given as follows:
Ni + 2HF → NiF2 + H2
Based on the above equation, 2 moles of HF will react to produce 1 mole of NiF2.
According to this question, to make 174 grams of NiF2, we find the number of moles of HF required. However, we first convert the mass value of NiF2 to mole value using;
mole = mass/molar mass
Molar mass of NiF2 = 58.7 + 19(2)
= 58.7 + 38
= 96.7g/mol
mole = 174/96.7
mole = 1.799mol of NiF2
Hence, if 2 moles of HF will react to produce 1 mole of NiF2.
- 1.799mol of NiF2 will require (1.799 × 2) = 3.598
= 3.6mol of HF.
Complete the sentence. _______ have the information to build proteins.
Select one:
Segments of nucleotides called genes
Segments of DNA called RNA
Segments of DNA called genes
Segments of nucleotides called RNA
Answer:
Segments of DNA called RNA.Good luck dude
What is an important effect of gravity?
A. It causes radioactive particles to split off from the nucleus.
B. It is responsible for charge attraction.
C. It keeps the nucleus of the atom together.
D. It maintains the distances between planets.
SUBMIT
Answer:
d. It maintains the distances between planets.
Explanation:
In the illustration, which solute will dissolve first?
00.0
00.0
tanka
tank
Solute in Tanks A and B will dissolve at equal rates.
Solute in Tonk Awill dissolve first
Soluten Tork B wil dissolves
The first to dissolve is the solute in tank B. The amount of a substance that dissolves in a specific solvent concentration at a specific temperature is known as its solubility.
Which phase of the dissolving process is the first?The introduction of a solute to a solvent is the first stage in the dissolving process. The molecules of these two substances begin to interact, causing the solute molecules to disperse and become encircled by solvent molecules.
Which of the following three compounds dissolves in water?In water, salt, sugar, and coffee all dissolve. They disintegrate quickly. They typically dissolve more rapidly and completely in hot or warm water. Even very hot water won't be able to dissolve sand or pepper.
To know more about temperature visit:
https://brainly.com/question/14633960
#SPJ1
What type of shape do solids have?
hope it helps :-). good morning.
22. Sodium-24 has a half-life of 15 hours. How much sodium-24 will remain in an 42.0-g sample after 90 hours?
Answer:
The answer would be 0.65625
1.How many grams of zinc Zn and oxygen O2 will be needed to form 324 grams of ZnO after the reaction?
Answer: pretty sure its 0.214 moles * 40.3g/mole = 8.6g (2 sig figs) of MgO, and
0.035 moles * 40.3g/mole = 1.4g of MgO
Explanation:
Given the reaction:
Zn(s) + 2 HCl(aq) → Zn2+(aq) + 2 C1-(aq) + H2(g)
If the concentration of HCl(aq) is increased, the
frequency of reacting collisions will
a) decrease, producing a decrease in the reaction rate
b) decrease, producing an increase in the reaction rate
c) increase, producing a decrease in the reaction rate
d) increase, producing a increase in the reaction rate
Answer:
d) increase, producing a increase in the reaction rate
Explanation:
How many moles are in 1.4 x 10^21 atoms of sodium?
Answer:
devide by avogadro constant 6.02*10^23
Explanation:
If you use 65.34 g of Al2S3, how many grams of AICl3 can be produced?
Answer:
sorry po
indi ko po maintindihan
A gas of certain mass occupies a volume of 650cm^3 under a pressure of 750 mm Hg. Calculate the pressure under which the volume of gas will be reduced by 10 percent of its original volume.
Answer:
7500 mmHg
Explanation:
From the question,
Applying Boyles Law,
PV = P'V'................ Equation 1
Where P = original pressure, P' = final pressure, V = Original Volume, V' = Final Volume.
make P' The subject of the equation
P' = PV/V'.............. Equation 2
Given: P = 650 cm³, P = 750 mmHg, V' = (650×10/100) = 65 cm³ (Reduced by 10 percent of it original volume)
Substitute these values into equation 2
P' = (650×750)/65
P' = 7500 mmHg
Which of the following metals would be the best to choose for making jewellery? Aluminium, iron, copper or gold?
Answer:
Of course the answer is gold
Explanation:
Gold is used for making jewellery and not aluminium,iron or copper
Answer:
copper or gold.
Explanation:
Copper is also a good material for accessories. Even in the ancient times, those who can’t afford gold jewelry wear copper jewelry instead. It offers design flexibility too due to its high ductility.
Please help!! I have 10 minutes left!!
Answer:
I believe it is hydrogen for the first and methane for the second.
Explanation:
Answer to 8: The most dangerous or harmful gas to humans in the atmosphere would be carbon dioxide. But reserchers have found that methane levels in ancient air samples and found that scientists have been vastly underestimating the amount of methane humans are emitting into the atmosphere via fossil fuels.
Answer to 7: The type of gases present are as critical to density as elevation and gravity, and all are interrelated. Certain atmospheric gases will create thick atmospheres. For example, atmospheres with abundant hydrogen tend to be thicker as gases will combine with hydrogen for greater mass.
Hope this helps!
do you really get 7 years of bad luck if you crack a mirror :(
Answer:
nope its a myth don't worry :)
Are electron shells or orbitals actually inside the atom or are they outside of the structure of the atom?
Answer:
Electrons in atoms occupy energy levels, also called electron shells, outside the nucleus . Different shells can hold different maximum numbers of electrons. The electrons in an atom occupy the lowest available energy level first. This is the shell nearest the nucleus.
Explanation:
Which theories from the past contributed to today's plate tectonic theory?
O The theory of continental drift and the big bang theory.
O The big bang theory and the theory of natural selection.
O The theory of continental drift and the theory of sea floor spreading.
O The theory of sea floor spreading and the theory of relativity.
Answer:
I believe it's the second one
Explanation:
The big bang theory and the theory of natural selection.
The theory of continental drift and the theory of sea floor spreading from the past contributed to today's plate tectonic theory. Therefore, option A is correct.
What is continental drift ?Continental drift is the theory that the Earth's continents have moved relative to one another over geologic time, giving the appearance of "drifting" across the ocean floor.
Plate tectonics caused continental drift over millions of years. Plate tectonics also explained how plate movement causes volcanoes and earthquakes, as well as how continent collisions create massive mountain ranges.
In the early twentieth century, a scientific theory known as continental drift was proposed to explain this migration of continents. That theory was initially dismissed, but it paved the way for another theory known as plate tectonics, which scientists now accept as an explanation for how the Earth's continents move.
Thus, option A is correct.
To learn more bout the continental drift, follow the link;
https://brainly.com/question/15122129
#SPJ6
How many grams of water can be vaporized by 2.153 kJ of energy?
Answer:
That is, water has a high heat of vaporization, the amount of energy needed to change one gram of a liquid substance to a gas at constant temperature. Wate
Explanation:
PLEASE ANSWER ASAP!!!! i need it now
Answer:
não sei ainda mas acho que e A
Answer:
e c f
Explanation:
read the question and it tells you how to do it and I can get you to help
BRAINLIESTT
The pH of a solution is 8.43. What is it {H3O+}concentration?
A. 3.7 x 10-3
B. 2.7 x 10-6
C. 1.0 x 10-14
D. 1.0 x 10-8.43
Answer:
D. 1.0 x 10-8.43
Explanation:
The pH is an unit of concentration in chemistry used to determine the acidity -or basicity- of a particular solution. Is used in quality control to determine the security of a product for consumers.
The equation is:
pH = -log [H₃O⁺]
As pH = 8.43:
8.43 = -log [H₃O⁺]
10^-8.43 = [H₃O⁺]
1.0x10 -8.43 = [H₃O⁺]
Right option is:
D. 1.0 x 10-8.43A 0.239 gram sample of a gas in a 100-ml flask exerts a pressure of 603 mm Hg at 14 Celsius. What is the gas? (Hint: don’t forget BRINCLHOF)
A) chlorine
B) nitrogen
C) krypton
D) xenon
D) oxygen
Please help me and explain how u got ur answer
Answer:
A) chlorine
Explanation:
To solve this question we can use:
PV = nRT
In order to solve the moles of the gas. With the moles and the mass we can find the molar mass of the gas to have an idea of its identy:
PV = nRT
PV / RT = n
Where P is pressure: 603mmHg * (1atm / 760mmHg) = 0.7934atm
V = 100mL = 0.100L
R is gas constant = 0.082atmL/molK
T is absolute temperature = 14°C + 273.15 = 287.15K
0.7934atm*0.100L / 0.082atmL/molK*287.15K = n
3.37x10⁻³ moles of the gas
In 0.239g. The molar mass is:
0.239g / 3.37x10⁻³ moles = 70.9g/mol
The gas with this molar mass is Chlorine, Cl₂:
A) chlorinepls help!!!!
Predict the missing component
in the nuclear equation.
1331 → X + -e
A
B
с
131 Cs
131Xe
1311
55
54
53
Answer: b
Explanation:
its b
The missing component in the nuclear equation.1331 → X + -e will be 131Xe54. option B is correct.
What is nuclear reaction?The particles in the nucleus are changed, and one element is transformed into another element when particles in the nucleus are gained or lost.
Nuclear reactions are processes in which one or more nuclides are produced from the collisions between two atomic nuclei or one atomic nucleus and a subatomic particle.
This was the first observation of an induced nuclear reaction, that is, a reaction in which particles from one decay are used to transform another atomic nucleus.
The most notable man-controlled nuclear reaction is the fission reaction which occurs in nuclear reactors. A target nucleus are within the range of nuclear forces for the time allowing for a large number of interactions between nucleons.
therefore , option B is correct.
Learn more about nuclear reaction , here :
https://brainly.com/question/10104286
#SPJ2
-
-
The pressure for a tire is 123 KPa. Calculate the pressure in atmospheres (atm)?
Answer:
0.974 atm; 740 mm Hg; 98.7 kPa; 0.987 bar