Phenol red is a common ph indicator. you add phenol red to an unknown substance and it turns yellow. what does this indicate about the ph of the substance?
The pH of the substance is less than 6.8.
Phenol red is a pH indicator that changes color depending on the acidity or basicity of the solution it is added to. When phenol red is added to a solution, it exhibits a range of colors: it is yellow in acidic solutions (pH less than 6.8), red or pink in neutral solutions (pH around 6.8 to 8.2), and purple or red-violet in basic solutions (pH greater than 8.2). Since the phenol red turned yellow upon addition to the unknown substance, this indicates that the pH of the substance is less than 6.8, meaning it is acidic.
Which element has a mass percent composition of 54.50% in vitamin c, c6h8o6?
The element with a mass percent composition of 54.50% in vitamin C (C6H8O6) is Oxygen. This is determined by calculating the contribution of oxygen's mass relative to the total molecular mass. Therefore, oxygen constitutes approximately 54.50% of the mass in vitamin C.
The element with a mass percent composition of 54.50% in vitamin C (ascorbic acid) is Oxygen (O). To determine this, you would calculate the mass percent composition of each element in the compound.
Given the molecular formula of vitamin C is C6H8O6 and its molecular mass is 176 amu:
Oxygen's atomic mass is 16 amu.
The mass contribution of oxygen in C6H8O6 is
6 atoms x 16 amu/atom
= 96 amu.
The mass percent composition of oxygen is given by:
(96 amu / 176 amu) x 100%
≈ 54.55%.
This calculation shows that Oxygen accounts for about 54.50% of the mass in vitamin C.
A 0.3870-g sample of a compound known to contain only carbon, hydrogen, and oxygen was burned in oxygen to yield 0.7191Â g of co2 and 0.1472Â g of h2o. what is the empirical formula of the compound?
Final answer:
The empirical formula of the compound containing 40.0% C, 6.71% H, and 53.28% O is C₁H₂O₂.
Explanation:
The empirical formula can be determined by calculating the molar amounts of carbon and hydrogen in the sample based on the masses of carbon dioxide and water produced. In this case, the sample contains 40.0% carbon, 6.71% hydrogen, and 53.28% oxygen. Assuming a 100 g sample, we would have 40.0 g of carbon, 6.71 g of hydrogen, and 53.28 g of oxygen. Converting these masses to moles using the molar masses of the elements (carbon: 12.01 g/mol, hydrogen: 1.008 g/mol, oxygen: 16.00 g/mol), we find that we have 3.3333 moles of carbon, 6.6683 moles of hydrogen, and 3.33 moles of oxygen. Dividing these values by the smallest mole value gives a ratio of 1:2. Therefore, the empirical formula of the compound is C₁H₂O₂.
How to write a balanced chemical equation from empirical formula?
To write a balanced chemical equation from an empirical formula, identify the reactant and products, write an unbalanced equation, balance the elements one by one, and make sure to use whole numbers. It's important to note that the final equation must reflect the law of conservation of matter.
Explanation:To write a balanced chemical equation from an empirical formula, you need to follow a few steps:
Identify the empirical formula. Say, we have C₂H₆.Identify the reactant and products. In this case, we have O₂ as the reactant and H₂O and CO₂ as products.Set up an unbalanced equation: C₂H₆ + O₂ → H2O + CO2.Balance the elements one by one. Start with carbon (C): C₂H₆ + O₂ → 2CO2 + H2O; then balance the hydrogen (H): C₂H₆ + O₂ → 2CO2 + 3H2O.Finally, balance the oxygen (O) on both sides. This could result in a fraction (since there could be an odd number of oxygen atoms), but that's acceptable for intermediate steps: C₂H₆ + 7/2O₂ → 2CO2 + 3H2O.However, we generally prefer to use whole numbers, so if you do have fractions, multiply everything by 2: 2C₂H₆ + 7O₂ → 4CO2 + 6H2O.This process ensures that the final balanced equation reflects the law of conservation of matter, where the numbers of each type of atom are equal on both sides of the equation.
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A microspectrophotometer measures which of the following?
Electrons
Electricity
Light absorption
Pigments
Answer : The correct option is, Light absorption
Explanation :
Microspectrophotometer : It is a type of instrument that measures the spectra of the microscopic sample by using the different wavelengths of an electromagnetic radiation.
It is designed to measure the the spectrum of the microscopic sample. It is also measure the transmittance, absorbance, polarization and fluorescence of the microscopic sample.
From the given options, the option light absorption is the correct option.
Hence, a microspectrophotometer measures the light absorption.
Answer:
Light absorption
Explanation:
At stp, 1.0 l br2 reacts completely with 3.0 l f2, producing 2.0 l of a product. what is the formula of the product? (all substances are gases.)
Answer:
BrF3
Explanation:
Find moles of Br2 and F2 with Pv=nrt formula , then, divide by smallest to find empirical formula
Read the measurement. how many milliliters are shown? 34 ml 38 ml 39 ml 40 ml
Answer:
B
Explanation:
CHEMISTRY HELP !!!!
1. If you were to grind up a pepperoni pizza and test it for each of the macromolecules, what color would each test tube turn? For each macromolecule listed, (give the color that the solution would change if it is present.)
Pizza Test Tube / Color of solution
Starch
Protein
Lipid
When testing a pepperoni pizza for macromolecules, an iodine solution will turn blue-black for starch, a Biuret reagent will turn purple for protein, and fats will create transparent oil stains on paper. The Benedict's solution will change color from green to reddish-orange if reducing sugars like glucose are present.
If you were to grind up a pepperoni pizza and test it for each of the macromolecules, you would expect different colors in test tubes indicating the presence of those macromolecules. Specifically, the colors will change based on the reactions of the food components with certain chemicals.
Starch: If there is starch in the pizza, you would use an iodine solution for testing. The presence of starch would turn the iodine solution from its original orange-brown color to a blue-black color.Protein: The Biuret reagent is commonly used to test for proteins. If proteins are present, the solution would change to a purple hue.Lipids: The test for lipids, such as fats and oils, is known as the fat emulsion test. After crushing a piece of the pizza with ethanol and allowing it to evaporate, the appearance of transparent oil stains on paper would indicate the presence of lipids.In the context of the specific examples provided, when Benedict's solution is added and the mixture is heated, a positive result for the presence of reducing sugars like glucose would change the solution to a range of colors from green to reddish-orange, depending on the quantity of the reducing sugar.
Which gas sample STP has the same total number of molecules at 2.0 L of CO2(g) at STP
5.0L
2.0L
6.0L
When zinc (or aluminum) was allowed to react with the copper sulfate what was the limiting reagent?
How does the reaction of hydrogen and oxygen to produce energy in a fuel cell differ from their interaction during the direct combustion of hydrogen and oxygen?
In a fuel cell, hydrogen and oxygen produce electrical energy through an electrochemical reaction, with high efficiency and low pollution. Direct combustion of hydrogen and oxygen, on the other hand, yields thermal energy with significant energy loss due to thermodynamic limitations.
Explanation:The reaction of hydrogen and oxygen to produce energy in a fuel cell differs substantially from their interaction during the direct combustion of hydrogen and oxygen. In a fuel cell, hydrogen is oxidized at the anode, and oxygen is reduced at the cathode, which results in water as a byproduct and the production of electrical energy directly via an electrochemical reaction. This process is efficient, producing electricity with up to 50%-75% energy efficiency.
In contrast, the direct combustion of hydrogen and oxygen is a much less efficient process, as it generates energy in the form of heat through a combustion reaction. The energy released in direct combustion, when used to power a heat engine, succumbs to second-law thermodynamics constraints, resulting in at least half of the energy being "wasted" to the surroundings with only about 20%-25% energy efficiency.
Moreover, fuel cells are nonpolluting, significantly reduce greenhouse gas emissions, and contribute to less dependence on fossil fuels. However, challenges like economic viability and dependence on natural gas for hydrogen production still hinder the wide adoption of fuel cell technology for applications like fuel-cell vehicles (FCVs).
How many valence electrons are in an atom of phosphorus? (atomic number 15)?
Answer:
Connexus D,B,B,A,A
Explanation:
Which of the following would introduce bias into an experiment?
A. publishing your experimental results in a scientific journal
B. allowing other scientist to repeat and verify your experimental results
C. using a computer to record ans tore your data
D. discarding data that does not fit with your personal expectations
Why didn't mendeleev use atomic number to arrange the elements?
The primary reason for this was that Mendeleev
didn't know that atomic numbers actually existed. Atomic numbers
were only discovered a period after Mendeleev's time. The use of X-rays made it
possible to find the atomic number, and those had not been discovered yet.
The periodic table was then arranged in 1913 by Henry Moseley
in an arrangement according to atomic number.
How does the composition of a mixture of hydrogen and oxygen differ from the composition of a compound containing hydrogen and oxygen
How many valence electrons does holmium have?
How many electrons will a calcium (ca) atom gain or lose in forming an ion?
_______ is the spontaneous nuclear change of isotopes with unstable nuclei.
The Ability of a material to be drawn into a thin wire is called??
Ductility is the ability of a material, usually a metal, to be drawn into thin wires. This property is particularly significant in industries that rely on flexible, resilient materials.
Explanation:The ability of a material to be drawn into a thin wire is known as ductility. Ductility is a property pertaining to a material's ability to deform under tensile stress, which is typically seen in metals such as copper or gold. A high degree of ductility means that a material can be stretched into a long, thin wire without breaking. This property is important when considering materials for things like electrical wiring, jewelry making, or any process where a thin, flexible wire is needed.
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what crystals are formed when a molten ceramic cools slowly
Bigger crystals of rock are formed when a molten ceramic cools slowly.
What is the igneous process?Igneous rock can be described as one of the three rock types, sedimentary and metamorphic. Igneous rock can be formed through the cooling and solidification of magma or ceramic.
The magma derives from partial melts of rocks in either a mantle or crust. The melting is caused by three processes: an increase in temperature, a decrease in pressure, or a variation in composition.
Solidification occurs either below the surface and can form with crystallization to form granular, crystalline rocks to form natural glasses.
The rate of cooling the ceramic determines the size of the crystals of the rock. If the ceramic cools down slowly then it takes a longer period of time, therefore, the grain size will be bigger. If the ceramic cools rapidly then it takes a shorter period of time, therefore, the grain size will be smaller.
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The only large land mass(es) not part of a sovereign state is/are
In the Periodic Table, atoms in the same _______ have the same number of valence electrons, and tend to have similar chemical behavior. A. column B. diagonal C. row D. All of the Above E. None of the Above
During which intervals is potential energy decreasing and average kinetic energy remaining constant?
In a nuclear reaction, mass must be lost to produce energy. Please select the best answer from the choices provided T F
Is breaking an egg an example of a physical or chemical change? explain your answer.
b.is cooking an egg an example of a physical or chemical change? explain your answer?
Breaking an egg is an example of a physical change. This is because the egg was broken, thus its physical appearance was different. If you were to cook the egg, that would be a chemical change because that would result in a new chemical formation of the stuff inside of the egg. But since you're only breaking the egg, it's just a physical change.
I guess that answers both questions.
Hope that helped!
Answer:
Because the egg is broken in Physical Change.
Explanation:
Boiled Egg is inside the cooking rice in Chemical Change.
Write a balanced equation for the reaction of solid iodine with fluorine gas.
The balanced equation for the reaction of solid iodine with fluorine gas is I2(s) + 3 F2(g) → 2 IF3(g), indicating one molecule of iodine reacts with three molecules of fluorine to form two molecules of iodine trifluoride.
Explanation:The student asked for a balanced chemical equation for the reaction between solid iodine (I2) and fluorine gas (F2). The balanced equation for this reaction is:
I2(s) + 3 F2(g) → 2 IF3(g)
This equation indicates that one molecule of solid iodine reacts with three molecules of fluorine gas to produce two molecules of iodine trifluoride gas. In balancing the equation, it is important to ensure that the same number of each type of atom appears on both sides of the equation.
How many protons, neutrons and electrons are there in a neutral atom of the isotope of lithium named lithium-6?
A neutral atom of lithium-6 contains three protons, three neutrons, and three electrons, with an isotope symbol of 6Li or 3Li.
Explanation:The neutral atom of the isotope lithium-6 contains three protons, three neutrons, and three electrons. The atomic number for lithium, which signifies the number of protons in an atom, is always 3. The mass number of lithium-6 indicates that it has a total of six protons and neutrons, meaning this isotope has three neutrons since the number of protons is known to be three. The isotope symbol for lithium-6 is either 6Li or 3Li, with the mass number given as the superscript before the elemental symbol (Li).
There are __________ naturally occuring elements.
a.71
b.92
c.103
d.112
All the elements of a family in the periodic table have what feature in common?a)they all have similar chemical properties.b)they all have the same number of protons in the nucleus.c)they are all located in the same horizontal row or period.d)they all have the same number of electrons in the electron cloud.
A) They all have similar chemical properties.
A decimeter (dm) is one tenth of a meter. The diameter of Earth is 1.3 x 104 km. What is the diameter expressed in decimeters?
1.3 × 107 dm
1.3 × 1011 dm
1.3 × 108 dm
1.3 × 10–5 dm
A decimeter (dm) is one tenth of a meter are the unit of length of measurement. The diameter of Earth is 1.3 x 104 km., the diameter expressed in decimeters is 1.352 x 10^7 dm so it is the first one.
What are the unit of length measurement ?It can be defined as the measuring of the length of objects with some specific units representing the symbol and it can divided into standard or non-standard.
Some measuring tools are ruler, measuring tape used to determine the length. For example, the height of students can be measured using a feet scale, some units of length measurements are inches, centimeters, meters, feet, etc
The units of length measurement are two types such as Standard and non-standard units of measuring length.
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