Answer:
a new substance is produced
Explanation:
i just took my test and got this question right
The best evidence that a chemical reaction occurs when coal burns is a new substance is produced. The correct option is A.
What is coal?Coal is a carbon containing fossil fuel, which is formed when the organic matter is decomposed inside the earth with heat and pressure by the earth crust. It is the most used fossil fuel.
Carbon dioxide is a gas produce when these fossils fuel burned. It is a green house gas and increase the warmth of the earth when produced. It is taken by plants to make their food.
When coal burns, it produces carbon dioxide which is a gas and coal is a solid, so here the chemical reaction is happening which is producing a new substance.
Thus, the correct option is A. A new substance is produced.
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A radioactive isotope has a half life of 25 minutes. How many half lives have occurred after 175 minutes?
5
6
7
8
Will give Brainliest
Answer:
7
Explanation:
What does the questions “how much?” and “how many?” have in common?
The Sun is a constant supply of energy to Earth.
A. True
B. False
Whats the answer to 7/2 × 1/5?
Answer:7/10
Explanation:multiply top and bottom
what is the compound of scI2
Answer:
sulfur dichloride
Explanation:
SCl2 is the chemical formula for sulfur dichloride. This compound is made of only two elements, so it is a binary compound.
Which is not a reason that water is used to store spent fuel rods from nuclear power plants?
Water increases the speed of the chain reaction in the fuel rods.
Water protects nuclear power plant workers from the high temperature and radiation of the fuel rods.
Water acts as a radiation shield to reduce the radiation levels.
Water cools the spent rods.
Answer:
I believe the answer would be A
The enthalpies of formation of the compounds in the combustion of methane, , are CH4 (g): Hf = –74.6 kJ/mol; CO2 (g): Hf = –393.5 kJ/mol; and H2 O(g): Hf = –241.82 kJ/mol. How much heat is released by the combustion of 2 mol of methane? Use .
Answer:
The amount of energy released from the combustion of 2 moles of methae is 1,605.08 kJ/mol
Explanation:
The chemical reaction of the combustion of methane is given as follows;
CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (g)
Hence, 1 mole of methane combines with 2 moles of oxygen gas to form 1 mole of carbon dioxide and 2 moles of water vapor
Where:
CH₄ (g): Hf = -74.6 kJ/mol
CO₂ (g): Hf = -393.5 kJ/mol
H₂O (g): Hf = -241.82 kJ/mol
Therefore, the combustion of 1 mole of methane releases;
-393.5 kJ/mol × 1 + 241.82 kJ/mol × 2 + 74.6 kJ/mol = -802.54 kJ/mol
Hence the combustion of 2 moles of methae will rellease;
2 × -802.54 kJ/mol or 1,605.08 kJ/mol.
Answer: answer is C
Explanation:
Just took the test
What is an example of a polyatomic ion
Answer: The hydroxide cation (OH -) and the phosphate cation (PO 4 3-) are both polyatomic ions.
Explanation:
Answer:
OH - and PO 4 3- are both polyatomic ions
Analysis: The limiting reactant(s) appeared to be
because
there is nothing with which it can react
Explanation:
The limiting reactant(s) prevents a reaction from continuing because there is none left.
Why do limiting reactants occur?Identification of the limiting reactant makes it possible to calculate the theoretical yield of a reaction. The reason there is a limiting reactant is that elements and compounds react according to the mole ratio between them in a balanced chemical equation.
How do you get the limiting reactant?The reactant that is consumed first and limits the amount of product(s) that can be obtained is the limiting reactant. To identify the limiting reactant, calculate the number of moles of each reactant present and compare this ratio to the mole ratio of the reactants in the balanced chemical equation.
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A child has a balloon in his house in the air conditioning. He goes outside with the balloon on a hot day. What happens to the temperature of the gas and volume of the balloon?
Answer:
There would be an increase in temperature and corresponding increase in the volume of the balloon
Explanation:
Charles law is been here
Charles law states that the volume of a given mass of gas is directly proportional to the temperature in Kelvin, provided that the pressure on the gas is kept constant. Mathematically Charles law can be represented thus;
V∝ T
Where V is the volume of the gas and;
T is the temperature.
Relating Charles Law to the question
The child moved outside from the room, constant atmospheric pressure is maintained.The temperature of the room is lower than the temperature outside.From Charles law postulation, there would be an increase in volume because of the increased temperature, since our pressure is same.
Addition of _____________ to pure water causes the least increase in conductivity
organic molecules
because organic molecules does not dissociate in water
How many moles of O2 are needed to react completely with 35.0 mol of 10 points
FeCl3? *
4FeCl3 + 302 — 2Fe2O3 + 3Cl2
A) 26.3 mol
B) 46.7 mol
C) 23.3 mol
D) 10.0 mol
Ideal Stoichiometry
Barium oxide has a replacement reaction with lithium. Calculate the mass of Barium oxide needed to react with 34.67 g of lithium.
*equation needed and thorough explanation please*
A- 340.5
B- 383.0
C- 455.0
D- 256.8
Answer:
the answer is 383.0
hope it is helpful
Which is the molar mass of Calcium?
Answer:
40.078 u
Explanation:
What are three examples of acid-base reactions in cooking
Answer:
Lemon juice baking soda and vinegar
Explanation:
How many times more acidic is a pH of 2 than a PH of 7?
Answer: 10 times more
Explanation:
The metabolic oxidation of glucose, C6H12O6, in our bodies produces CO2, which is expelled from our lungs as a gas.
C6H12O6(aq) + 6 O2(g) → 6 CO2(g) + 6 H2O(l)
Calculate the volume of dry CO2 produced at body temperature (37°C) and 0.960 atm when 24.5 g of glucose is consumed in this reaction.
Answer:
[tex]\large \boxed{\text{21.6 L}}[/tex]
Explanation:
We must do the conversions
mass of C₆H₁₂O₆ ⟶ moles of C₆H₁₂O₆ ⟶ moles of CO₂ ⟶ volume of CO₂
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 180.16
C₆H₁₂O₆ + 6O₂ ⟶ 6CO₂ + 6H₂O
m/g: 24.5
(a) Moles of C₆H₁₂O₆
[tex]\text{Moles of C$_{6}$H$_{12}$O}_{6} = \text{24.5 g C$_{6}$H$_{12}$O}_{6}\times \dfrac{\text{1 mol C$_{6}$H$_{12}$O}_{6}}{\text{180.16 g C$_{6}$H$_{12}$O}_{6}}\\\\= \text{0.1360 mol C$_{6}$H$_{12}$O}_{6}[/tex]
(b) Moles of CO₂
[tex]\text{Moles of CO}_{2} =\text{0.1360 mol C$_{6}$H$_{12}$O}_{6} \times \dfrac{\text{6 mol CO}_{2}}{\text{1 mol C$_{6}$H$_{12}$O}_{6}} = \text{0.8159 mol CO}_{2}[/tex]
(c) Volume of CO₂
We can use the Ideal Gas Law.
pV = nRT
Data:
p = 0.960 atm
n = 0.8159 mol
T = 37 °C
(i) Convert the temperature to kelvins
T = (37 + 273.15) K= 310.15 K
(ii) Calculate the volume
[tex]\begin{array}{rcl}pV &=& nRT\\\text{0.960 atm} \times V & = & \text{0.8159 mol} \times \text{0.082 06 L}\cdot\text{atm}\cdot\text{K}^{-1}\text{mol}^{-1} \times \text{310.15 K}\\0.960V & = & \text{20.77 L}\\V & = & \textbf{21.6 L} \\\end{array}\\\text{The volume of carbon dioxide is $\large \boxed{\textbf{21.6 L}}$}[/tex]
How many senses does the human body have?
O A. 3
B. 5
Answer:
B
Explanation:
sight, hearing, smell, taste and touch
Answer:
Most easiest answer..
There are 5 senses in human body.☺️
Which of the following did Antoine Lavoisier correctly characterize as an element? light silicone dioxide mercury
Answer: mercury
Explanation: I looked up the answer to your question.
Answer:
Mercury
Explanation:
I did this question and I got it right.
The element hydrogen has the highest specific heat of all elements. At room temperature, hydrogen's specific heat is 14.30 J/g •°C. If the temperature of a 340.0 g sample of hydrogen is to be raised by 30°C, how much energy will have to be added to the hydrogen?
Answer:
THE ENERGY NEEDED TO BE ADDED TO RAISE THE TEMPERATURE BY 30°C IS 145, 860 J
Explanation:
The energy needed can be calculated by using the heat formula, which is;
Heat = m c ΔT
m = mass of the hydrogen = 340 g
c = specific heat capacity of hydrogen at room temperature = 14.30 J/g°C
ΔT = change in temperature = 30°C
Heat =?
So therefore,
Heat = 340 * 14.30 * 30
Heat = 145860 J
The energy needed to be added to the hydrogen to bring the mass of 340 g to an increased temperature of 30°C is 145, 860 J or 145.86kJ
Which answer gives both a positive impact and a negative impact associated with the effects of nitrogen- and phosphorus-enhanced fertilizers?
A- increased algal blooms and damage to drinking water
B- increased plant growth and damage to drinking water
C- increase in denitrifying bacteria and increase in plant growth
D- increase in a limiting resource and increase in denitrifying bacteria
Answer:
The answer is B
Explanation:
Answer:
Which answer gives both a positive impact and a negative impact associated with the effects of nitrogen- and phosphorus-enhanced fertilizers?
1. increased algal blooms and damage to drinking water
Right Answer 2. increased plant growth and damage to drinking water
3. increase in denitrifying bacteria and increase in plant growth
4. increase in a limiting resource and increase in denitrifying bacteria
Explanation:
Leon made a study chart about human-induced changes to
the environment.
Which headings best complete the chart?
Environmental Changes Caused by Humans
X: Habitat Destruction
Y: Pollution
Y
Results from
introducing harmful
substances into the
Results from natural areas
being cleared and replaced
by human development
© X: Long-Term Changes
Y: Short-Term Changes
X: Short-Term Changes
Y: Long-Term Changes
0 X: Pollution
Y: Habitat Destruction
environment
Example: deforestation
Example: oil spill
The question was not well arranged above. It has been arranged in the answer below.
Question:
Leon made a study chart about human-induced changes to the environment.
Environmental Changes Caused by Humans
X Y
Results from introducing harmful substances into the environment
Example: oil spill
Results from natural areas being cleared and replaced by human development
Example: deforestation
Which headings best complete the chart?
X: Habitat Destruction
Y: Pollution
X: Long-Term Changes
Y: Short-Term Changes
X: Short-Term Changes
Y: Long-Term Changes
X: Pollution
Y: Habitat Destruction
Answer:
X: Pollution
Y: Habitat Destruction
Explanation:
From the above question, Leon gave us two variables, X and Y.
The human induced changes were divided into two.
1. Results from introducing harmful substances into the environment
Introducing harmful substances into the environment is also called pollution. And we can represent this as X which is the first variable.
2. Results from natural areas being cleared and replaced by human development.
This description given in number two above whereby land areas are been cleared and replaced by human development has a negative effects on the environment because the vegetation which includes the trees are been cut down and living organisms(animals) will go extinct gradually. This act affect the balance of the ecosystem and it can be referred to as the destruction of the habitat of living organisms
Therefore, the correct headings best complete the chart is :
X: Pollution
Y: Habitat Destruction
Answer:
what the top person said
Explanation:
☺
What happens when kmno4 is heated
Answer:
kmno4 is heated => k2mno4 + mno2 + o2
Hope this helps!
:)
Which of these conclusions is correct about P and Q in the diagram?
P represents the land and Q represents the ocean.
P represents the ocean and Q represents the land.
P represents the land and Q represents the atmosphere.
P represents the atmosphere and Q represents the ocean.
Answer:
P represents the atmosphere and Q represents the ocean.
Explanation:
Answer the questions using the drop-down menus.
Which is the independent variable in this experiment?
Which is the dependent variable in this experiment?
Which is a controlled variable in this experiment?
In the experiment to measure the heat absorbed by a material placed in
the Sun, we have;
The independent variable is either the angle of insulation or the type of materialThe dependent variable is the temperature of the materialThe controlled variable is the type of material when the angle of insulation is the independent variable and vice versaWhat differentiates the given experimental variables?The possible experiment is with regards to the factors that influence energy from the Sun
The factors investigated are;
The type of material and the angle of lighting (insulation) affects the absorption of heat
The independent variable is the variable that is the cause of the effect
measured in the experiment.
It is the variable that the researcher has control over or controls and
varies during the experiment to produce the measured effect.
In the above experiment, the independent variable are either ;
The angle of insulation or the type of material respectivelyThe dependent variable is the variable that is under test or that is being measured.
In the above experiment the dependent variable is the temperature of the material which can be measuredThe controlled variable is the variable that remains the same or is held
constant during the experiment and can be used as reference to
compare the dependent variable.
In the experiment, the controlled variable are either;
The type of material when the angle of insulation is the independent variable or vice versaLearn more about independent and dependent variables here:
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Answer:
angle of light
temperature of material
type of material
Explanation:
E d g e 22 !
how many number of electrons are in aluminium and nitrogen in their free state?
Answer:
MRCORRECT has answered the question
Explanation:
13 electrons
So... for the element of ALUMINUM, you already know that the atomic number tells you the number of electrons. That means there are 13 electrons in a aluminum atom. you can see there are two electrons in shell one, eight in shell two, and three in shell three.
7 electrons
So... for the element of NITROGEN, you already know that the atomic number tells you the number of electrons. That means there are 7 electrons in a nitrogen atom. Looking at the picture, you can see there are two electrons in shell one and five in shell two.
Calculate the molar mass of ammonium chloride
Answer:
53.491 g/mol
Explanation:
Create the chemical compound and find each individual element's molar mass. Lastly, add them up.
1. Calculate the molarity of 35g of calcium chloride (CaCl2) that is dissolved in 850ml of water. (Calculate moles first)
a. 0.27M
b. 0.38M
c. 0.32M
d. 0.80M
2. Calculate the molarity of 90g of copper sulfate (CuSO4) when dissolved in 5 L of water.
a. 0.112M
b. 2.8M
c. 0.56M
d. 0.50M
3. What is the molarity of NaOH if 0.70 moles are dissolved in 250 ml of water?
a. 175,000M
b. 2.8M
c. 0.175M
d. 4M
4. How many moles of Lithium oxide (Li20) are in 2 L of solution with a molarity of 2.0M?
a. 1 mole
b. 2 moles
c. 0.2 moles
d. 4 moles
5. How many moles of NaCl are in 7.5 L of 0.5M?
a. 3.75 moles
b. 15 moles
c. 0.066 moles
d. 2.5 moles
Answer:
yo I got same question do u know it
If a body was lying on their back when they died, and was moved to their front after 12 hours, where would one see the skin discoloration from pooling blood?
Answer:the parts of the body which is nearest to the ground ie thier back will show discoloration
Explanation:
If the body remains at a position for long hours, the parts of the body which is nearest to the ground can develop a skin discoloration as a result of pooling of blood in the tissues and this is called livor mortis, which tends to be permanent from 8Hours upwards.
Write the full symbol for the isotope of oxygen having 8 neutrons.
Answer:
Isotopes are forms of a chemical element that have the same atomic number but differ in mass. 16O → 8 protons + 8 neutrons; a “light” oxygen); The relative amounts are expressed as either 18O/16O or δ 18O Oxygen - 18 (aka 18O → 8 protons + 10 neutrons; a “heavy” oxygen).
