Answer:
. a pure substance consists only of one element or one compound.
. a mixture consists of two or more different substances, not chemically joined together
Pure water consists of 11. 19% hydrogen by weight and 88. 81% oxygen by weight. what does the law of constant proportions tell you about a 100 g sample of pure water?
Answer:
The law of constant proportion states that the percentage of each compound will stay constant regardless of the source size.
In other words, since 11.19% + 88.81% = 100%, in a 100 gram sample, these percentages will stay the same. In this case, 100% is "equal" to 100 grams.
So, 11.19 grams hydrogen and 88.81 grams oxygen will be present in a 100 gram sample of pure water.
Treatment of Poison oak
Answer:
Apply cool compresses to the skin. Use topical treatments to relieve itching, including calamine lotion, oatmeal baths, Tecnu, Zanfel, or aluminum acetate (Domeboro solution). Oral antihistamines, such as diphenhydramine (Benadryl), can also help relieve itching.
CH4(g) + 2O2 (g) →CO2(g) + 2H2O (l), ΔH = -890kj/mol
Calculate much heat is released when 3.5 moles of methane gas undergo a combustion reaction
A combustion reaction is a reaction that reacts with oxygen to produce the product. 3.5 moles of methane release - 3115 kJ/mol of heat.
What is a combustion reaction?A combustion reaction is a chemical reaction that involves the burning of the reactant in the presence of the oxygen molecule to release heat.
The balanced reaction of methane combustion is given as:
CH₄(g) + 2O₂ (g) → CO₂(g) + 2H₂O (l), ΔH = -890 kJ/mol
From the reaction, it can be said that 1 mole of methane combusts to produce -890kJ/mol enthalpy.
So, 3.5 moles will produce, 3.5 × -890kJ/mol = - 3115 kJ/mol.
Therefore, 3.5 moles of methane produce - 3115 kJ/mol heat.
Learn more about combustion reaction here:
https://brainly.com/question/11886957
#SPJ1
An increase in the population of an organism would most likely be associated with which of the following?
Answer:
An expansion of suitable living space
Explanation:
Increase occurs in the population of the organism only occurs when there is a suitable environment present for that organism. Suitable environment means that place where all the needs of the organism are available such as food, water and shelter etc. If food and water are present in large amount and decrease in animals occurs that prey on that organism will increase the population of the organism.
One form of energy can transform into another form of energy.
17 Energy in a flashlight's battery changes from ________ energy to electrical energy.
Answer:
Chemical
Explanation:
Chemical energy is stored in the batteries of a flash light. When the flashlight is used, the Chemical energy that was stored, is then used to make Electrical energy for the flashlight. Then electrical energy is converted to heat in the filament of the flashlight bulb. Some of the heat is lost to the surroundings, and some is converted into light energy.
Please help me with this chemistry
Answer:
57)a)increase
b)increase
c)pressure
58)
A way of describing a chemical change that indicates what substances were present before the change and what substances are present after the change is called a _____.
A. chemical equation
B. chemical formula
C. chemical bond
D. All of the above
E. None of the above
Answer:
[tex]\\ \rm\dashrightarrow Chemical\: Equation [/tex]
Explanation:
When a chemical change happens or chemical reaction happens something yields at reactants and something at products
Representing them is called chemical equation
I need help I will give crown
Answer:
This is a scientific model.
Explanation:
A scientific model is a representation of systems of ideas, events or processes.
This drawing offers explanations that enables the water cycle to be predicted.
9. An empty, massless cube is measured to have all sides equal to 11 cm. It is floating in water and will slowly be filled with sand
that has a density of 3.5 g/cm'. What volume of sand will cause the box to sink?
sink: w cube+w sand>Fb(buoyant force)
w cube = massless = 0
w sand>Fb
w sand > 1000 x 10 x (11/100)³
w sand > 13.31 N
ρgV sand > 13.31
3.5 x 10³ x 10 x V sand > 13.31
V sand = 13.31 : 3.5 x 10⁴ = 3.803 x 10⁻⁴ m³ = 380.3 cm³
What is the mass of 11.5 moles of lithium
Answer:
1 moles =6.9g
11.5moles= x
then we have x=79.35g
A gas occupied 780.0 mL at a temperature of 30°C. Several days later, it was measured at
a temperature of 16°C.
What volume did the gas occupy under these new conditions?
Answer:
744.0 mL
Explanation:
Formula obtained from Charles Law :
⇒ [tex]\frac{V_{1} }{T_{1} } = \frac{V_{2} }{T_{2} }[/tex]
===============================================================
Given :
⇒ V₁ = 780.0 mL
⇒ T₁ = 30 °C = 303 K
⇒ T₂ = 16 °C = 289 K
=============================================================
Solving :
⇒ V₂ = 780 × 289 / 303
⇒ V₂ = 225420 / 303
⇒ V₂ = 744.0 mL (approximately)
What is the process of removing salt from seawater.
Answer:
Explanation:
Process of desalination is used to remove salt from seawater for provision of fresh water
is there enough oxygen for complete combustion?
Answer:
Complete combustion occurs when there is enough oxygen to completely use up all the reactants. Incomplete combustion occurs when there is not enough oxygen resulting in the production of smoke, and less energy is produced when compared with complete combustion.
Continued deforestation will most likely lead to _______. a. a decrease in the number of endangered species b. an increase in the number of endangered species c. an increase in the number of oil and chemical spills d. a decrease in glacial melting please select the best answer from the choices provided a b c d
Deforestation often leads to an increase in the number of endangered species of plants and or animals.
What is deforestation?Deforestation refers to the conversion of forests to non-forest uses. In other words, it is the removal of forest layers for non-forest reasons.
Since forests represent a hotspot for plant and animal biodiversity, their removal automatically means a decrease in biodiversity.
Endangered species are species of plants and animals that are under the threat of going extinct either due to natural or anthropological effects.
Thus, deforestation often leads to an increase in the number of endangered species.
More on deforestation can be found here:https://brainly.com/question/11697527
#SPJ4
Answer:
b
Explanation:
How many moles are in 1.24 * 10^25 of carbon?
Answer:
2.059800664 x 10^47 moles
Explanation:
Using the rules below,select ALL compounds that are soluble
Answer:
NaNO3 is the answer of given statement
Which of the following equation is balanced?
Answer:
2fe2o3+3c=4fe+3co2
Explanation:
because 2×2 =4 fe &2×3=6 so we put it like 3co2
Justify how dstv has been regarded as an example of a monopoly with the nature of product
When natural conditions are present in a free market then, the natural monopoly arises. Dstv is unique and has no other substituents that make them an example of monopoly.
What is a monopoly?Monopoly is the dominance of a single product, goods, service, business, etc. in the market or the economic sector that excludes the other competitors. They can be the single seller that sells in the business.
DStv is a monopoly in America and includes natural gases, electricity, and communication services. It has no other competitor in the market and has control over others. They are the sole service provider and have no close substitutes.
Learn more about monopoly here:
https://brainly.com/question/27791498
#SPJ1
What volume (in mL) of 0.750 M sodium hydroxide is needed to neutralize (react with) 275 ml of 0.500 M sulfuric acid (H2SO4)?
NaOH + H2SO4 -> H2O + Na2SO4
I NEED WORK
We know the formula
C1V1=C2V2C is concentration and V is volume
0.750V1=275(0.5)0.75V1=137.5V1=183.34mLThe new volume will be by using the relation between molarity and volume formula.
What is molarity?Molarity, also termed as molar concentration in a solution, is a method of determining how much material is present in a chemical solution.
Calculation of volume with the aid of molarity formula is shown below:
Volume is calculated by using the molarity formula.
[tex]M_{1} V_{1} = M_{2} V_{2}[/tex]
Where, M is molarity and V is volume.
It is given that, [tex]M_{1}[/tex] = 0.750 M , [tex]M_{2}[/tex] = 0.500 M, [tex]V_{1}[/tex] = 275 ml .
Now, put the value of given data in molarity formula.
[tex]M_{1} V_{1} = M_{2} V_{2}\\V_{2} = M_{1} V_{1} / M_{2}\\V_{2} = (0.750 M) (275 ml) / 0.500 M\\V_{2} = 183.34 ml[/tex]
Therefore, the volume will be 183.34 ml.
To know more about molarity click here.
https://brainly.com/question/2817451.
#SPJ2
express 3.81 meters in inches
Answer:
150 inches.Explanation:
3.81 m. = 150 inches.
I can't find explanation. Hope this is my best!
I'm going to give brainlyest (image below)
Answer:
it stays the same
Explanation:
Even though the volume of water changes as it becomes ice, the mass of the water should remain the same before and after it turns into ice.
Balance the following reactions:'
Mg(OH)2 + HCl ➡️ H2O + MgCl2
Ca(ClO3)2 ➡️ CaCl2 + O2
Ca(NO3)2 + ➡️ KBr CaBr2 + KNO3
Al + HCl ➡️ AlCl3 + H2
C2H6 + O2 ➡️ CO2 + H2O
[tex]2 HCl + Mg(OH)_2[/tex] → [tex]2 H_2O + MgCl_2[/tex]
[tex]3 Ca(ClO)_2[/tex] → [tex]2 CaCl_2[/tex] + [tex]Ca(ClO_3)_2[/tex]
[tex]2 KBr + Ca(NO_3)_2[/tex] →[tex]2 KNO_3 + CaBr_2[/tex]
[tex]2Al +6HCl[/tex] → [tex]2AlCl_3 +3H_2[/tex]
[tex]2C_2H_6+7O_2[/tex] → [tex]4CO_2+6H_2O.[/tex]
What is a balanced chemical equation?A balanced chemical reaction is an equation that has equal numbers of each type of atom on both sides of the arrow.
Balanced chemical equation:
[tex]2 HCl + Mg(OH)_2[/tex] → [tex]2 H_2O + MgCl_2[/tex]
[tex]3 Ca(ClO)_2[/tex] → [tex]2 CaCl_2[/tex] + [tex]Ca(ClO_3)_2[/tex]
[tex]2 KBr + Ca(NO_3)_2[/tex] →[tex]2 KNO_3 + CaBr_2[/tex]
[tex]2Al +6HCl[/tex] → [tex]2AlCl_3 +3H_2[/tex]
[tex]2C_2H_6+7O_2[/tex] → [tex]4CO_2+6H_2O.[/tex]
Learn about the balanced chemical equation here:
https://brainly.com/question/24245953
#SPJ1
d. What is being done to save this species
e. An organization/group that is working towards
Create a commercial that showcases why we should save the manta rays
a. Commercials should be about 30seconds-1 minute. No longer than 30
Answer:
answer
Explanation:
I think it's e hope it right
5. When calcium carbonate is heated, the following reaction occurs:
CaCOJ – CaO + COz (a)
The standard enthalpy of reaction for each substance is shown below.
Substance
AH, (kJ/mol)
-1206.9
-635.1
CO2 (9)
-393.5
What statements correctly classifies the decomposition of calcium carbonate
reaction?
CaCO3 (5)
CaO(s)
A-The reaction is endothermic because energy is released during the
reaction.
B-The reaction is endothermic because energy is absorbed during the
reaction.
C-The reaction is exothermic because energy is released during the
reaction.
D-The reaction is exothermic because energy is absorbed during the
reaction.
Answer:
B-The reaction is endothermic because energy is absorbed during the
reaction
Explanation:
CaCO3 -> CaO + CO2
endothermic means cooling
its decomposition of limestone to calcium oxide (quicklime) and carbon dioxide on heating
byjus
The equilibrium concentrations for the reaction between N2 and O2 to form NO at a certain temperature are given in the table below. What is the equilibrium constant for the reaction?
A. 42
B. 2.4 x 10^-2
C. 4.2 x 10^-4
D. 21
Answer:
c
Explanation:
c is correct i believe
How do you think the light would travel if the laser pointer was 1000 meters away?
20 pnts!!!!!!!!!!!!!!!!!!!!!
It totally depends on the laser power (mW). The divergence of the light is depending on it.
What is a laser?A device that uses stimulated emission of photons from excited atoms or molecules to produce a strong beam of coherent monochromatic light is a laser.
When electrons in optical materials like glass, crystal, or gas absorb energy from an electrical current or light, a laser is formed.
When a 5mW 650 nm laser glows on a white surface in complete darkness, we can see it from 500 to 1 km distant.
Because of the divergence, the projected dot 1 km distant will be a huge dot with a diameter of 20–30 m30 m and will be extremely dim.
Hence,It totally depends on the laser power (mW). The divergence of the light is depending on it.
To learn more about the laser, refer to the Link ;
https://brainly.com/question/14783882
#SPJ1
Which of the following statements is true? Select one: a. A solution is a pure substance. b. A solution is a mixture. c. The solvent is dissolved in the solute. d. A solution has the same properties as a colloid.
Answer:
B
Explanation:
What does the number at the end of an element mean? (For example, Hydrogen-3)
Answer:
The top number is the total mass number, particles in an atom of an element that have mass are protons and neutrons.
Explanation:
Which salt is produced when sulfuric acid and calcium hydroxide react completely.
Answer:
calcium sulphate and water
Why do ice cubes float to the top of a glass of water.
Answer:
Since the water is heavier, it displaces the lighter ice,
Explanation:
hope that helps
