Answer:
4.002602 u
Explanation
Answer:
4.002602 u
Explanation:
Consider:
2Al (s) + 3Cl2 (g) ----> 2AlCl3 (s) ΔH=-1390.81 kJ
Which of the following correctly describes he magnitude and direction of the enthalpy change when 10.0g of AlCl3 forms?
a. 104.4 kJ, exothermic
b. 52.2 kJ, exothermic
c. 26.1 kJ, exothermic
d. 52.2 kJ, endothermic
e. 26.1 kJ, endothermic
Answer:
The answer is B.
Explanation:
1 mole of AlCl3 = 27 + 3*35.5 grams = 133.5 grams
1 mole / 133.5 = x / 10 Cross multiply
133.5 x = 1 * 10
x = 10 / 133.5
x = 0.0749 moles
Delta H when written the way it is, is on the left side and since it is negative, the reaction must give away 1390.81 kj. The reaction is exothermic.
So now you get the answer between AB and C by setting up a ratio.
2/0.0749 = -1390.81 / x Cross multiply
2x = 0.0749 * -1390.81
2x =- 104.18 Divide both sides by 2
2x//2 = -104.18 / 2
x = -52.09
B
When doing medical research with human subjects, which four limitations are unavoidable?
Answer:
Answer
The limitations are-
1. Privacy of the individuals involved in the research process.
2. Physical and psychological risks should be minimized
3. The subjects should be chosen equitably
4. Only reasonable exposure to risks is admissible.
Explanation
The privacy of the individuals involved in the research must be taken into consideration. This will ensure safety of patient data and information. The risk of physical and physiological well being of the person must be taken into consideration in such a research. In addition to that, the subject must be made to understand every procedure and the risks involved before testing. Moreover, only minimal exposure to risks is allowed and must have been previously tested in animals to avoid deaths.
What is a small description of a molecule
Answer:
molecule, a group of two or more atoms that form the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance.
The electronic transition in a hydrogen atom from n = 6 to n = 3 emits electromagnetic radiation having a higher frequency than a transition
from n = 5 to n = 3
What determines an object’s ability to float?
what is the total amount of energy absorbed by the substance as it completely changes from a solid at 40 degrees to a gas at 200 degrees
Answer:
I don't know the answer sorry man
Can you give a definition of what Sodium Hydroxide
Answer:
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na⁺ and hydroxide anions OH⁻
Explanation:
Also can you mark me as brainliest.
What is the mass % of acetone in a 1.85 M solution of acetone (MM = 58.08 g/mol) in water? The density of the solution is 0.971 g/mL.
A 1.85 M acetone solution (MM = 58.08 g/mol) with a density of 0.971 g/mL has a mass percent of acetone of 11.0%.
What is the mass percent?It refers to the mass of solute in 100 grams of solution.
Let's suppose we have 1 L of the solution.
Step 1: Calculate the mass of solute (acetone).We have a 1.85 M solution of acetone (MM = 58.08 g/mol). We will calculate the mass of acetone using the following expression for molarity.
M = mass acetone / MM acetone × liters solution
mass acetone = M × MM acetone × liters solution
mass acetone = 1.85 mol/L × 58.08 g/mol × 1 L = 107 g
Step 2: Calculate the mass of the solution.We have 1 L (1000 mL) of the solution with a density of 0.971 g/mL.
1000 mL × 0.971 g/mL = 971 g
Step 3: Calculate the mass percent of acetone.%acetone = (107 g/971 g) × 100% = 11.0 %
A 1.85 M acetone solution (MM = 58.08 g/mol) with a density of 0.971 g/mL has a mass percent of acetone of 11.0%.
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Plz help me plz will give Brainly
Explanation:
a brittle, High melting solid : option B (MgCl2).
1) H2S
2) H2O
3) I2
weakest to strongest.
hope this helps you.
5. The density of a gas is lower than the density of a liquid because:
a. gas atoms are smaller than liquid atoms.
b. gas atoms are larger than liquid atoms
c. atoms in a gas are farther apart than atoms in a liquid.
d. atoms in a gas are closer together than atoms in a liquid
Answer:
c
Explanation:
the gas is further apart and the liquid is closer together
How many mL of 1.76 M sodium hydroxide solution (strong base) must be added to 0.75
Macetic acid to make 683 mLa pH 49 buffer? (pka of acetic acid is 4.76)
Answer: Special care is required to prepare a solution of sodium hydroxide or NaOH in water because considerable heat is liberated by the exothermic reaction. The solution may splatter or boil. Here is how to make a sodium hydroxide solution safely, along with recipes for several common concentrations of NaOH solution.
Explanation:
Hope this helps!
The change in internal energy for the combustion of cyclohexanol (C6H12O) is -890.7 Kcal per mole. A .708 g sample of cyclohexanol undergoes complete combustion in a bomb calorimeter that has a heat capacity of 2.70 Kcal per degree C. What is the final temperature of the water in the calorimeter if the initial water temperature is 27C?
The final temperature in the calorimeter, with a heat capacity of 2.70 kcal/°C, internal energy for the combustion of cyclohexanol (C₆H₁₂O) of -890.7 kcal/mol and initial temperature of 27°C, is 29.33 °C.
We can find the final temperature of the water in the calorimeter with the following equation:
[tex]\Delta E = -C\Delta T = -C(T_{f} - T_{i})[/tex] (1)
Where:
ΔE: is the change in internal energy for the combustion of C₆H₁₂O = -890.7 Kcal/mol
C: is the heat capacity of the calorimeter = 2.70 Kcal/°C
[tex]T_{f}[/tex]: is the final temperature =?
[tex]T_{i}[/tex]: is the initial temperature = 27 °C
By solving equation (1) for [tex]T_{f}[/tex], we have:
[tex] T_{f} = -\frac{\Delta E}{C} + T_{i} [/tex]
[tex]T_{f} = -\frac{-890.7 \frac{kcal}{mol\: C_{6}H_{12}O}*\frac{1 mol \: C_{6}H_{12}O}{100.158 g \: C_{6}H_{12}O}*0.708 g \: C_{6}H_{12}O}{2.70 kcal/^{\circ}C} + 27 ^{\circ}C = 29.33 ^{\circ}C[/tex]
Therefore, the final temperature of the water is 29.33 °C.
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Which statement describes the bonds in nitrate (NO3-)?
A) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is polar covalent, with oxygen pulling the electrons toward it.
B) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is nonpolar covalent.
C) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is ionic.
D) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is polar covalent, with nitrogen pulling the electrons toward it.
The bond in NO3- ion is polar covalent and oxygen pulls the electrons.
A polar covalent bond is formed when there is a significant difference in electronegativity between covalently bonded atoms.
Such bonds are said to be polar covalent with the electron density tilted towards one of the bonding atoms.
In NO3-, Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is polar covalent, with oxygen pulling the electrons toward it.
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The answer is A, Nitrogen and oxygen have an electronegativity of 0.5, so the bond is polar covalent, with oxygen pulling the electrons toward it.
Electronegativity is defined as, a value that describes the relative strength with which an atom of an element attracts electrons to itself in a chemical bond. Moreover, electronegativity can be used to define a bond.
A electronegativity of 0.5-1.7 is determined to be a polar covalent bond, thus the bonds in nitrate is polar covalent.
We know that electronegativity increases on the periodic table across a period, but decreases down a group. Thus, oxygen has a greater electronegativity than nitrogen.
PLS HELP WORTH 25 POINTS WILL MARK BRAINLIEST IF CORRECT
Examine the false statement. When pressure is added to a reaction at chemical equilibrium, the reaction responds by increasing the amount of pressure it exerts on its surroundings. Select the rewording that makes the statement true.
A. When pressure is added to a reaction at chemical equilibrium, the reaction responds by increasing the rate of reaction, which will decrease the number of particles and offset the pressure.
B. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it exerts on its surroundings.
C. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by increasing the rate of reaction, which will decrease the number of particles and increase the pressure.
D. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it releases to its surroundings.
E. When pressure is added to a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it absorbs from its surroundings.
IT'S NOT C OR E
Answer:
A i think. Good luck!!!!
Calculate the number of days after the explosion for a sample of iodine-131 to go from 100%
iodine-131 to less than 1% iodine-131. Complete chart.
It will take 56 days to go from 100% iodine-131 to less than 1% iodine-131.
From the table, we can see that the half life of iodine-131 is 8 days. We can see that it takes 8 days to have 50% of iodine-131
After 16 days, we will have 25 % of iodine-131
After 24 days, we will have 12.5 % of iodine-131
After 32 days, we will have 6.25% of iodine-131
After 40 days, we will have 3.125% of iodine-131
After 48 days, we will have 1.5625% of iodine-131
After 56 days, we will have 0.78125% of iodine-131
After 56 days, the percentage of iodine-131 drops to less than 1%.
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1. ATOMIC RADIUS: For each of the following sets of atoms, rank the atoms from smallest to largest atomic radius.
a. Li, C, F
b. Li, Na, K
c. Ge, P, O
d. C, N, AI
Answer:
The answer is letter C
how many moles of of Al are needes to form 2.43 mol of Al2Br6?
A. 7.29 mol
B. 1.22 mol
C. 2.43 mol
D. 1.62 mol
E. 4.86 mol
Answer:
c
Explanation:
c .
answer
your
this
questions
5. A student measures the mass of an object three times on a balance in order to calculate the objects
density. The recorded masses are 70.21 g, 64.55 g, and 74.70 g. The accepted value for the mass of
the object is 70.21 g.
a. Are these measurements accurate? Why or why not?
b. Are the measurements precise? Why or why not?
Answer:
This is not chemistry this is physics
Why do you think dark surfaces absorb radiation better than light surfaces?
Your answer→ The lighter side absorbs less of the incident light, reflecting some of the energy. Darker materials also emit radiation more readily than light-colored materials, so they cool faster.
To solve this we must be knowing each and every concept related to radiation. Therefore, dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.
What is radiation?According to the energy of the emitted particles, radiation is frequently classified as being either ionizing or non-ionizing. More than 10 eV is often carried by ionizing radiation, which is sufficient to ionize atoms as well as molecules and rupture chemical bonds.
The word refers to radiation having an energy level high enough to ionize atoms, or to remove electrons from atoms to produce ions. Whenever an electron is removed from an atom's electron shell, or, as we may say, when it is "tried to knock out," the action of ionization takes place. Dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.
Therefore, dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.
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what is the difference between exergonic and exothermic reactions?
Answer:
An exergonic reaction is a type of chemical reaction that releases free energy to the surroundings. The final state of this reaction is less than its initial state. ... “Exothermic” literally means “outside heating” while “exergonic” literally means “outside work.”
Explanation:
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Have a happy day <3 Miss Hawaii
According to the law of conservation of matter, which statement about chemical reactions is true? A. Atoms cannot be created or destroyed by chemical reactions. B. Atoms are created by some reactions and destroyed by others. C. Energy is created as atoms are destroyed in chemical reactions. D. Every atom destroyed in a chemical reaction must be replaced.
Protons and neutrons have opposite, but equal magnitude, charges. An atom contains the same number of protons and electrons Neutrons and electrons are found in the nucleus of an atom. Protons have about the same mass as electrons. Electrons make up most of the mass of an atom. which one is true about subatomic particles
Answer:
the true statement is an atom contains the same number of electron and protonExplanation:
let us see the behaviour of the sub atomic particles
nutrons and protons found in the nucleus of an atoman atom have the same number of electron and proton but they have different chargenutron is chargeless particlemost mass of the atom concentrated in the nucleus of an atomelectrons have almost 0 mass from an atommass of proton and mass of nutron are equvalent or almost equalthere are many properties of subatomic particles i have listed some of them above .
I think it is help ful for youhelppppppppppppppppppppppppp
True
All matter is made up of atoms.
im guessing it probably true
Please solve this question
Answer:
what question?
Explanation:
HELPPPPPP
Calculate the frequency of light with a wavelength 559nm
Answer:
Refer to the attachment
what element has a high content of brilliant yellows color
Answer: , sulfur and gold are most obviously yellow.
Explanation: Phosphorus, arsenic and antimony have allotropes which are yellow or whitish-yellow; fluorine and chlorine are pale yellowish gases.
Câu 15: Nguyên tử X nặng gấp 2 lần nguyên tử cacbon. Nguyên tử X đó có nguyên tử khối và
kí hiệu hóa học là
A. 24_Mg. B. 16_O C. 56_Fe D. 32_S
Answer:
A
Explanation:
can someone help me please ... god will bless u if u help...it is very urgent... i only have 1hr to answer this question
Answer:
iuiwusiwuiqihihiuwusbhwubduywbduywbudb me no esspanlo
Explanation:
niuniniuniuniun
If you have 4.01 g of H2, how many grams of NH3 can be produced?
Answer:
136.5886g of NH3
Explanation:
N2 + 3H2 = 2NH3
The mass of the N2 = 4.01
3H2 has a 2/1 ratio
This means the mass of 3H2 is twice as much as N2.
NH3= 2*N2 = 2*4.01 = 8.02 of NH3
Then, by multiplying the mass by MX (17.031)
8.02*17.031=136.5886g can be produced. Round it if needed.
What mineral is composed of sodium chloride (NaCl)?
Answer:
Salt
Explanation:
The mineral form halite , or rock salt is sometimes called common salt