What quantity of magnesium (in grams) is needed to supply the energy required to warm 30 mL of water (density = 1.00 g/mL) from 22°C to 90°C?
Answers
Answer:
0.22 grams of magnesium
This seems too low, so check the calculations/
Explanation:
How is the heat delivered? Is the magnesium hot and added to the water? If so, at what temperature.
Is the heat generated from an exothermic chemical reaction?
=================
I'll assume here that the heat comes from the reaction of magnesium with water. The balanced equation is:
Mg + 2H2O = Mg(OH)2 + H2
It has a heat of reaction of −924.7 kJ/mol.
We need enough Mg to heat 30 ml of water from 22°C to 90°C. The specific heat of water is needed. It is 4.184 J/g-K. It tells us that 4.184 Joules are needed to raise the temperature of water by 1 degree K.
30 ml of water with density 1 gram/ml means we have 30 grams of water. (We'll ignore the water that is added from the chemical reaction.).
Lets calculate the Joules required to raise 30 grams of water from 22°C to 90°C. Note that the specific heat has units of g and Kelvin. Since we need a temperature change, the number value for ΔT is the same for both °C and °K. So the temperature change is +68°K.
We can now calculate the Joules required:
(30 grams H2O)*(4.184 J/g-K)*(+68°K) = 8535.4 Joules or 8.5 kJ to 2 sig figs.
The Mg/H2O heat of reaction of −924.7 kJ/mol. will allow us to calculate the amount of Mg needed to supply 8.5 kJ. The minus sign tells us that the reaction RELEASES energy (the energy leaves the "system" of Mg and H2O).
Calculate the moles of Mg needed to release 8.5 kJ:
(924.7 kJ/mole)*(x moles) = 8.5 kJ
x moles = 0.0092 moles
Whoa. That is only (0.0092 moles)*(24.03 g/mole) = 0.22 grams of magnesium
This seems low to me, so check on the heat of reaction figure I used. And don't let the hydrogen get away.
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Answers
Answer:
31.43 ml of sulfuric acid is needed to react with 23.1 g of barium peroxide.
Explanation:
For the reaction:
BaO₂(s) + H₂SO₄(aq) ⇒ BaSO₄(s) + H₂O₂(aq)
We need 1 mole of BaO₂ to react with 1 mole of H₂SO₄ and then forming 1 mole of BaSO₄ and 1 mole of H₂O₂.
We know that 4.5 M solution of H₂SO₄ means 4.5 moles of H₂SO₄ in 1000 ml of solution.
Then,
23.1 g BaO₂ × ×
×
= 31.43 ml H₂SO₄
169g : 98g
23.1g : mx
mx = [23.1*98g]/169g ≈ 13.4g
Mr = 98g/mol
n = 13.4g/98g/mol ≈ 0.14mol
Cm = 4.5M
n = 0.14mol
V = 0.14mol/4.5mol/dm³ ≈ 0.031L = 31mL
(2) C, N, Ne, Ar (4) Na, Zn, As, Sb
Answers
No reason why you shouldn't be able to do it yourself. If you need a good online one check out ptable.org.
Anyways...
Series 1 is the correct answer. Beryllium is an (alkaline earth) metal, silicon is a metalloid, chlorine is a (halogen) nonmetal, and krypton is a noble gas.
(Series 2...carbon is a nonmetal, nitrogen is a nonmetal, neon is a noble gas, and argon is a noble gas...there is no metal or metalloid.
Series 3...potassium is an (alkali) metal, iron is also a metal, boron is a metalloid, and fluorine is a (halogen) nonmetal. There is no noble gas.
Series 4...sodium is an (alkali) metal, zinc is a metal, arsenic is a metalloid, and antimony is a metalloid...there is no noble gas.)
(1) Be, Si, Cl, Kr is the list of elements that includes a metal, a metalloid, a nonmetal, and a noble gas.
Shiny, malleable, ductile, and good at transferring heat and electricity are the characteristics of a metal. Metal beryllium (Be) is one.A substance with characteristics of both metals and nonmetals is referred to as a metalloid or semi-metal. Metalloid silicon is known as Si.
An element without metallic characteristics is referred to as a nonmetal. At ambient temperature, nonmetals are frequently gases or brittle solids. A nonmetal is chlorine (Cl).An element in group 18 of the periodic table that is inert and has a difficult time forming chemical compounds is referred to as a noble gas. A noble gas is krypton (Kr).
Learn more about metals, here:
#SPJ6
Will mark brainliest to correct answers
1. What happens in a chain reaction?
A) Products that start a new reaction are released.
B) Reactants that have two parts split
C) Products that are radioactive are lost
D) Radioactive reactants are deposited on control rods
2. Which type of coolant(s) usually is (are) used to remove heat from nuclear reactor core?
A) water only
B) liquid sodium only
C) liquid sodium or water
D) CFCs
3. A reaction that results in the combining of smaller atomic nuclei is ___.
A) chemical
B) fission
C) fussion
D) ionization
4. What does neutron absorption accomplish in a nuclear reactor?
A) It slows down the reaction.
B) It speeds up the reaction
C) It increases the rate of heat absorption
D) It recycles the fuel
Answers
Answer:
C B A D
Explanation:
Answers
Answer:
The answer is 8.00 moles
Explanation:
To find the number of moles in a substance given it's number of entities we use the formula
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
We have the final answer as
8.00 moles
Hope this helps you
Answers
Answer:
D i am prety shure
Explanation:
Answer:-D
Explanation:
picks up CO2 and O2
picks up O2 and releases CO2
releases O2 and CO2
Answers
Answer:
picks up O2 and releases CO2
Explanation:
The pulmonary artery represents a structure within pulmonary circulation that is responsible for carrying deoxygenated blood to the lung.
When blood from the pulmonary artery reaches the long, it becomes oxygenated an in return, the CO2 it carries is released into the lung in a process otherwise known as gaseous exchange.
What happens to the blood that reaches the lungs from the pulmonary artery? The blood that reaches the lungs from the pulmonary artery picks up O2 and releases CO2. The rest of the choices do not answer the question above.