Answer:
an organ system is formed when a group of organs works together to perform complex functions. it is composed of two or more tissue types and performs a specific set of tasks for the body
the valency of both Oxygen and magnesium is 2 give reason
Answer:
the valency of an element is its combining capacity that is the number of electrons it requires to lose, gain or share in order to become neutral.
[ An element can become neutral if it completes it's octet. That is if an element has 8 electrons in it'd outermost shell then it is considered neutral ]
The valence of Magnesium is 2 because it requires to lose 2 electrons to become neutral. whereas, the valence of Oxygen is 2 because it needs to gain 2 electrons to become stable.Hence they both have the same valence.
One may say that oxygen's valence is -2 while that of Magnesium is + 2. It's meaning is still the same but "-" sign indicates that oxygen will be gaining electrons in the process of becoming stable.
For a reaction: aA → Products, [A]o -4.3 M, and the first two half-lives are 56 and 28 minutes, respectively. Calculate k (without units). Show Work!
A. 7.7 x 10^-2
B. 4.2 x 10^-3
C. 3.8 x 10^-2
D. 8.3 x 10^-3
E. None of these
Answer:
C.[tex]3.8\times 10^{-2}[/tex]
Explanation:
We are given that
Initial concentration, [tex][A]_o=4.3 M[/tex]
First half life, [tex]t_{\frac{1}{2}}=56[/tex]minutes
Second half life, [tex]t'_{\frac{1}{2}}=28[/tex]minutes
We have to find K.
The given reaction is zero order reaction.
We know that for zero order reaction
[tex]t_{\frac{1}{2}}=\frac{[A]_o}{2k}[/tex]
Using the formula
[tex]56=\frac{4.3}{2k}[/tex]
[tex]k=\frac{4.3}{2\times 56}[/tex]
[tex]k=3.8\times 10^{-2}[/tex]
Hence, option C is correct.
Zero-order reactions are the reactions when a surface or a catalyst is required for the reaction to proceed and is saturated by the reactant chemicals. The result of the concentration versus the time plot will be a straight line in a zero-order reaction.
[tex]3.8 \times 10 ^{-2}[/tex] is the value of k.
How to calculate the value of k?Given,
Initial concentration [tex][A_{0}][/tex] = 4.3 MThe first half-life of the reactant [tex](t \dfrac{1}{2})[/tex] = 56 minutesThe second half-life of the reactant [tex](t \dfrac{1}{2})[/tex] = 28 minutesThe given reaction in the question is of zero-order and for that, we know that,
[tex]t \dfrac{1}{2} = \dfrac{[A_{0}] }{2\;\rm k}[/tex]
Substituting the values in the equation we get:
[tex]\begin{aligned}56 &= \dfrac{4.3 }{2\; \rm k}\\\\\rm k &= {4.3 }{2 \times 56}\\\\\rm k &= 3.8 \times 10^{ -2}\end{aligned}[/tex]
Therefore, option C is correct.
Learn more about the zero-order reaction here:
https://brainly.com/question/4638382
P +2 Fe +1 N+1 S+6 Mg +2
Answer:
= P + 2eF + N + S + 6gM + 2
Explanation:
Multiply: 1 . N = N
= P + 2eF + N + 1 . S + 6gM + 2
Multiply: 1 . S = S
= P + 2eF + N + S + 6gM + 2
Hope This Helps!
How many Hydrogen (H) Atoms are in Methylene?
Answer:
FOUR HYDROGEN ATOMS
Explanation:
Two C atoms, four H atoms, and two O atoms can also be arranged to form a methyl formate, which is used in manufacturing, as an insecticide, and for quick-drying finishes. Methyl formate molecules have one of the oxygen atoms between the two carbon atoms, differing from the arrangement in acetic acid molecules.
The Methylene group has 2 hydrogen. -CH2
What is the definition of a Brønsted-Lowry base? O A. A Brønsted-Lowry base transfers a proton to something else. OB. A Brønsted-Lowry base accepts a proton from something else. C. A Brønsted-Lowry base donates an electron pair to something else. O D. A Brønsted-Lowry base accepts a hydroxide ion from something else.
Answer:
the answer is option B it is a proton acceptor
TIMED PLS PLS HELP ASAP
The scattering of sunlight by the mixture of gas molecules in air results in the blue color of the sky. Calculate the energy (in Joules) of a single photon of blue light with a frequency of 6.00 × 10¹⁴ Hz. (h = 6.626 × 10⁻³⁴ J • s)
Answer:
It's me mario
Explanation:
Help please i beg someone answer and explain
Answer:
Q,N,1) lithium + hydrochloric -> lithium chloride + Hydrogen.
word equation ( 2li + 2HCl -> 2liCl + H2)A thief who has stolen large quantities of uranium-235 may have increased
the threat of what?
A. Alpha decay
B. Nuclear fusion
C. Nuclear waste
D. Proliferation
Since uranium - 235 decays by alpha decay, the thief runs a risk of exposure to alpha decay.
What is alpha decay?Radioactive decay is the sponteanous disintergration of a nuclide to yiled daughter nuclide and release energy.
We can see the decay of Uranium -235 in the image attached to this answer. Hence, it then follows that the theif here runs the risk of exposure to alpha decay.
Learn more about alpha decay: https://brainly.com/question/9904853
Answer:
D. Prolideration
Explanation:
Just took the test
what happens to the atomic size of elements on moving from left to right in a period of modern periodic table?
Answer: the atomic size will decrease
Explanation:
Answer:
It will remain the same because it is moving up and down to and fro it can not increase nor decrease or else will become an ion
La masa de una olla es de 300g y contiene 90% de aluminio. Hallar el número de moles de aluminio de la olla. P.A.(Al= 27)
Explanation:
The mass of a pot is 300g and contains 90% aluminum. Find the number of moles of aluminum in the pot. P.A. (Al = 27)
The mass of aluminum present in the pot is:
[tex]300 g * 90/100\\=270 g[/tex]
Hence, in the given pot 270g Al is present.
[tex]Number of moles of Al=\frac{given mass ofAl}{its molar mass}[/tex]
The gram atomic mass of Al -27 g/mol
Given the mass of Al is 270 g
Substitute these values in the above formula:
[tex]Number of moles of Al=\frac{given mass ofAl}{its molar mass}\\=\frac{270 g}{27 g} \\=10.0 mol[/tex]
Answer is 10.0 mol of Al is present.
What happens if kinetic energy of a gas is lowered
Answer:
"If you lower the kinetic energy of a gas its temperature will decrease because temperature is a measure of the average kinetic energy of a substance."
Explanation:
If an atom contains more
electrons than protons, it is
Answer:
If an atom has the same number of electrons as protons, it is a neutral atom.
Explanation:
Sodium and chlorine combine to form table salt.
2Na(s) + Cl2(g) → 2NaCl(s)
Does this reaction obey the law of conservation of mass?
Answer:
yes it does
Explanation:
because the ratios on the reactants and products are equal
The reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.
Yes, this reaction obeys the law of conservation of mass. The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; it is only rearranged.
In the given reaction, we have 2 sodium atoms (Na) on the left side and 2 sodium atoms (Na) on the right side. Similarly, we have 2 chlorine molecules (Cl₂) on the left side and 2 chlorine atoms (Cl) on the right side. Therefore, the number of atoms of each element is balanced on both sides of the reaction.
Additionally, the total mass of the reactants (2Na + Cl₂) is equal to the total mass of the product (2NaCl). The coefficients in the balanced equation represent the stoichiometric ratios, ensuring that the mass is conserved.
Hence, the reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.
Learn more about law of conservation of mass from the link given below.
https://brainly.com/question/28711001
#SPJ2
Which of these is correct please help
Answer:
NH4+
Explanation:
NH4+ is the acid and NH3 is the base, so NH4+ is the stronger acid.
Which is a mixture?
Sodium metal
chlonne gas
sodium metal and chlonne gas
sodium chlonde (salt) and water
Answer:
I believe it's salt and water
Explanation:
not sure
Answer:
Mixture is a electronic device used to peel the things such as onion ,tomato,ginger, garlic etc.
help please i am confused
It is pholem or phloem
Answer:
phloem I believe
Explanation:
dictionary
Which pair of substances would react the
fastest?
a. Copper sheet and concentrated
nitric acid.
b. Copper powder and dilute nitric acid
C. Copper powder and concentrated
nitric acid.
Answer:
C. It has the highest rate of reaction. Copper has the highest TSA/V and concentrated nitric acid has huggest num of solute
To begin the experiment, Xavier washed his hands and put on safety goggles. He then measured 120 milliliters of tap water, 2.5 milliliters of baking soda, and 2.5 milliliters of citric acid. The initial temperature of the water was 23.5°C.
Next Xavier added the baking soda and citric acid to the water. The mixture immediately began to bubble vigorously, which lasted for about 30 seconds. The new temperature of the mixture was 17.7°C.
Is a chemical reaction taking place during Xavier’s experiment? How do you know?
WILL GIVE BRAINLIEST!!!!!!!!!!!!!!!
Answer:
Yes a chemical reaction is taking place.
Explanation:
There is a change in temperature along with bubbling. All signs of a chemical reaction.
Which of these is a chemical property of a substance?
Answer:
A chemical property is a characteristic of a substance that may be observed when it participates in a chemical reaction. Examples of chemical properties include flammability, toxicity, chemical stability, and heat of combustion
when carbon is heated in a limited supply of oxygen, a gas is obtained.
1 .what is the name of this gas
Answer:
carbon monoxide
I think its correct but I am not sure
Answer: when carbon is heated in air carbon dioxide is formed, so is incomplete combustion which results in carbon monoxide.
Explanation: but when carbon dioxide reacts with more oxygen carbon monoxide is formed i guess.
I AM A BIT SURE BUT HOPE THIS HELPSSSS!!!!
Based on the Lewis/electron dot representation
of the two atoms, predict the ratio of metal
cationic (+) atom to nonmetal anionic (-) atom in
the compound.
.Ca.
.P.
A. 1:1
B. 3:2
C. 2:1
D. 3:1
Can someone plz tell me how to do this.
Answer:
B or C think so
I need help on this question pleas label
Answer:
we will solve your Quiz
Explanation:
kindly contact us for your chemistry QUIZ and BOOK it with us at gotit pro
helpe pls I will mark brainlest
Answer:
What is the question needing to be answered?
Explanation:
Usually with a scientific hypothesis, you ask the question in an if, then statement. For example: If it rains outside, then the ground will be wet. It's kind of like a cause and effect statement.
CORRECT ANSWER ONLY ND WILL GIVE BRAINLIEST✌
Calculate the mass of nitrogen dioxide gas that would occupy
the same volume as 10g of hydrogen gas at ē same pressure and temperature
(H= 1.0 N = 14.0 O= 16.0) GAS LAWS/MOLES
Answer:
150g
Explanation:
Assuming they are ideal gases at the same temperature and pressure, equal moles of gasses have equal volume. IN this case, if we have 10g of hydrogen gas, that is 5 moles of H2 gas. That means 5 moles og NO2 will occupy the same volume which is 5*(14.0 + 16.0*2) = 230 g
______ exhibits the highest
intermolecular forces of the states of matter.
A. Solid
B. Liquid
C. Gas
D. Vacuum

Calculate the number of hydrogen atoms in 33.0 g CH4
Answer:
The number of hydrogen atoms is 4.96x10²⁴.
Explanation:
The number of atoms can be found with the following equation:
[tex] n = N*\eta_{H} [/tex]
Where:
N: is the Avogadro's number = 6.022x10²³ atoms/mol
η: is the number of moles of hydrogen
n: is the number of hydrogen atoms
First, we need to find the number of hydrogen moles. The number of moles of CH₄ is:
[tex] \eta_{CH_{4}} = \frac{m}{M} [/tex]
Where:
m: is the mass of methane = 33 g
M: is the molar mass of methane = 16.04 g/mol
[tex] \eta_{CH_{4}} = \frac{33 g}{16.04 g/mol} = 2.06 mol [/tex]
Now, since we have 4 hydrogen atoms in 1 mol of methane, the number of moles of hydrogen is:
[tex] \eta_{H} = 2.06\: mol\: CH_{4}*4 \frac{mol\: H}{mol \: CH_{4}} = 8.24 mol [/tex]
Hence, the number of hydrogen atoms is:
[tex]n = N*\eta_{H} = 6.022 \cdot 10^{23} \: atoms/mol*8.24 mol = 4.96 \cdot 10^{24} atoms[/tex]
Therefore, the number of hydrogen atoms is 4.96x10²⁴.
I hope it helps you!
what is another name for hard water?
Answer:
Hyponym is the another name for hard water.
Explanation:
Please Mark me brainliest
why do scientists classify living things? ( I need 4 reasons why) thank you take care x
Answer:
1. To be able to easily name organisms
2. To ease communication among scientists
3. To give knowledge about the broad variety of organisms
4. To make the study of organisms easier
Fumaric acid, which occurs in many plants, contains, by mass, 41.4% carbon, 3.47% hydrogen, and 55.1% oxygen. The molecular mass of this compound is 116 amu. The molecular formula of this compound is
Question 15 options:
CHO
C3H3O
C3H3O3
C4H4O4
C6H6O6
Answer:
Explanation:
C = 41.4/12 = 3.43
H = 3.47/1 = 3.47
O = 55.1/16 =3.44
CHO is the skeletal formula (divide each by the lowest number above). The results are close enough to 1 to be 1.
(CHO)_x = 116
C + H + O = 29
(29) _ x = 116
x = 116/29
x = 4
So there area 4 carbons 4 hydrogens and 4 oxygens.
The correct formula is C4H4O4
Select all of the following reactions that are endothermic.
½N 2(g) + 3/2H 2(g) → NH 3(g) + 11.0 kcal/mole
H 2(g) + ½O 2(g) → H 2O(g), ΔH = -57.83 kcal/mole
½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)
½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole
NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole
Answer:
½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)
½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole
NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole
General Formulas and Concepts:
Thermochemistry
Endothermic vs ExothermicEnthalpyExplanation:
An endothermic reaction would have heat or energy gained in the final stage of the reaction.
This means that our enthalpy would be positive and heat/energy would be added as a reactant.
Out of all the answer choices, we see that only these have heat/energy added in the reactant side or the enthalpy being positive:
½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)
½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole
NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole
Topic: AP Chemistry
Unit: Thermochemistry
