Which feature of a balanced chemical equation demonstrates the law of conservation of mass?

The statement that describes a question that can guide the design of a scientific investigation could be about the necessity of a controlled variable. The correct answer is A.

It is a variable whose values are controlled by the researcher during the course of experimental investigations.

When designing an experiment, it is necessary to identify the different variables that would be involved for a successful investigation.

Variables can be independent, dependent, controlled, or constant. Identifying the necessary variables will help in designing the experiment.

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[tex]1) \text{ } \text{CaF}_{2}\\\\2) \text{ } \text{H}_{2}\text{S}\\\\3) \text{ } \text{NH}_{3}\\\\4) \text{ } \text{CCl}_{4}\\\\5) \text{ } \text{Na}_{2}\text{O}[/tex]

Avogadro's law states that in every mole of a substance, there are [tex]6.022 \times 10^{23}[/tex] molecules.

This means that in 2.3 moles, there are [tex]2.3(6.022 \times 10^{23})=\boxed{1.4 \times 10^{24} \text{ (to 2 sf)}}[/tex]

8.75 moles of oxygen will be left

The reaction is

Al(s) + O₂(g) -----> Al₂O₃(s)

On balancing the equation, we get:

4Al(s) + 3O₂(g) -----> 2Al₂O₃(s)

                      3/4 x 2 = 6/4 = 1.5 moles of aluminium oxide

                      3/4 x 3 = 9/4 = 2.25 mol of oxygen

8.75 moles of oxygen will be left

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Answer:

2.67 N

Explanation:

The normality equation looks like this:

Normality = Molarity (M) x Number of Equivalents

In this formula, the number of equivalents represents how many moles of the acidic species exist in the molecule. In other words, how many hydrogen atoms are in citric acid? This value would be 8 equivalents (as denoted by the subscript).

So, to find the normality, you need to (1) convert grams C₆H₈O₇ to moles (via molar mass), then (2) calculate the molarity (via molarity equation using moles and volume), and then (3) calculate normality (via normality equation using molarity and # of eq.).

(Step 1)

Molar Mass (C₆H₈O₇): 6(12.011 g/mol) + 8(1.008 g/mol) + 7 (15.998 g/mol)

Molar Mass  (C₆H₈O₇): 192.116 g/mol

128 g C₆H₈O₇             1 mole
----------------------  x  ----------------------  =  0.666 moles C₆H₈O₇
                                   192.116 g

(Step 2)

Molarity = moles / volume (L)

Molarity = 0.666 moles C₆H₈O₇ / 2 L H₂O

Molarity = 0.333 M

(Step 3)

C₆H₈O₇  -----> 8 hydrogen atoms

Normality = molarity x number of equivalents

Normality = 0.333 M x 8

Normality = 2.67 N

They're going to fall apart.

A system's entropy cannot decrease unless heat is being lost from it. This indicates that entropy cannot decrease in a closed system (i.e., nothing enters or leaves, and that means nothing at all), so it must either remain constant or rise. Entropy can decrease, rise, or stay constant in an open system when movement between the system and its surroundings is conceivable. Both of these outcomes leave open the option of a constant state.

Entropy:-

The quantity of atom-alignment combinations that can exist in a system is known as entropy. The quantity of energy that cannot be used for work can also be calculated from an object's entropy.

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Answer:

1.) Ionic

2.) Nonpolar Covalent

3.) Polar Covalent

Explanation:

Ionic bonding generally occurs when a metal and nonmetal wish to donate/receive electrons from each other. These bonds are between two atoms with a large electronegativity difference. In the first diagram, potassium (K) is a metal and chlorine (Cl) is a nonmetal. As you can see, after the reaction, potassium donates an electron to chlorine.

Nonpolar covalent bonding occur when atoms of practically the same electronegativity combine. As such, atoms of the same nature have a zero electronegativity difference and thus always form these bonds.

Polar covalent bonding generally occurs between two nonmetals. These atoms have an intermediate size electronegativity difference. Carbon (C) and chlorine satisfy this rule.

Answer:

its becuz the water is not capable to disolve all the salt it has limits and ones it reaches its limit it wont have the ability to disolve any salt

In an endothermic reaction, products are higher in potential energy and  less stable than reactants.

Endothermic reactions are those reactions that do not release heat but absorb heats, that's why the products are of higher potential energy and due to this they are less stable.

Thus, the correct option is C, higher; less.

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Considering the definition of volume, the volume of the box is 30 mL or 0.03 L.

Volume is a metric magnitude that is defined as the extension in three dimensions of a region of space. In other words, it is defined as the amount of space occupied by the object or figure in three-dimensional space. Volume is measured in cubic units.

Volume can be considered as the capacity of a container to hold a quantity of fluid (gas or liquid).

A box is a rectangular prism, which is defined as a prism with rectangular bases and rectangular lateral faces.

The volume of this prism depends on its three dimensions and is calculated as the multiplication of these dimensions:

Volume= Dimension 1× Dimension 2× Dimension 3

In this case, you know that a box has dimensions of 2.5 cm by 3.0 cm by 4.0 cm. So, the volume can be calculated as:

Volume= 2.5 cm× 3 cm× 4 cm

Solving:

Volume= 30 cm³

Being 1 cm³=  1 mL and 1 L= 1,000 mL then:

Volume= 30 cm³= 30 mL= 0.03 L

Finally, the volume of the box is 30 mL or 0.03 L.

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Atomic size decreases across a period because but the positive charge of the nucleus gets increases across a period.

The shielding effect is the shielding from the pulling force of the positively-charged nucleus given to. the outermost shell electrons by the inner electrons.

Since the shielding effect remains constant across a group but the positive charge of the nucleus gets bigger, atomic size decreases across a period.

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Answer:

Explanation:

The balanced equation for the decomposition of water is:

2H2O = 2H2 + 1O2

This tells us that we should expect 1 mole of O2 for every 2 moles of H2O, a molar ratio of (1 O2/2 H2O).

If we start with 2 moles of water, we should get (2mole H2O)*(1 O2/2 H2O) = 1 mole of H2.

But we are given just 20ml of water by the stingy boss.  We need to calculate the number of moles of water in that 20 ml.  We'll assume pure water at room temperature, so density = 1g/ml.  We have 20 g of H2O.  To find moles, divide by water's molar mass of 18 g/mole:

20g/(18g/mole) = 1.11 moles H2O

The moles of H2 produced would be:

(1.11 moles H2O)*(1 O2/2 H2O) = 0.55 moles O2 produced

We are not given the conditions of temperature and pressure, so the only way the calculate a volume of gas occupied by 1 mole of oxygen is to assume standard temperature and pressure (STP).  At STP 1 mole of gas occupies 22.4 liters.

1 mole of O2 will be 22.4 liters.

0.55 moles of O2 would be:

(0.55 mole O2)*(22.4 liters) = 12.32 liters

Answer:

Theoretically, Yes (See the explanation)

Explanation:

The body has enzymes that catalyze processes, as several other respondents have mentioned. I haven't noticed any comments, but the reverse impact might be just as significant. Some enzymes are reaction inhibitors. Others operate as both catalysts and inhibitors, depending on the amounts of the reactants and reaction products close to the catalyst. I'll provide an illustration to demonstrate how crucial inhibition may be. Let's say you consume three banana splits one after the other. That is a large number of calories. You would have a very high temperature and be so energetic and full of energy that you would be bouncing off the walls if all those calories were converted simultaneously into energy and heat. But neither you nor I have ever heard of overeating creating a high temperature or anxiety. This is due to the fact that many of the high energy molecules produced by the process hinder the enzymes that regulate metabolism, which produces the energy needed to power your body and generate heat. In other words, if you don't require high energy, your body won't keep making it. When there are huge amounts of carbohydrates around, the enzymes that turn the carbohydrates you consumed into glycogen and fat (to store the extra energy you don't need right now) become catalytic (mostly glucose). Therefore, the /majority of the energy from those three banana splits will be stored as fat and glycogen as it won't be needed. And that occurs as a result of the reaction to turn the sugars into energy being blocked by the lack of a demand for the energy at the time. Both enzymes that act as catalysts and those that act as inhibitors are essential to the healthy operation of our bodies.

________________________________________________________

Definitions:

Enzymes: Any of various proteins, as pepsin, originating from living cells and capable of producing certain chemical changes in organic substances by catalytic action, as in digestion.

Metabolism: The sum of physical and chemical processes in an organism by which its material substance is produced, maintained, and destroyed, and by which energy is made available.

Glucose: A sugar, C6H12O6, having several optically different forms, the common dextrorotatory form (dextroglucose, or -glucose) occurring in many fruits , animal tissues and fluids, etc., and having a sweetness about one half that of ordinary sugar, and the rare levorotary form (lavoglucose, or -glucose) not naturally occurring.

Chemical reaction: Reaction, the reciprocal action of chemical agents upon each other; chemical change.

Protein: Any of numerous, highly varied organic molecules constituting a large portion of the mass of every life form and necessary in the diet of all animals and other nonphotosynthesizing organisms, composed of 20 or more amino acids linked in a genetically controlled linear sequence into one or more long polypeptide chains, the final shape and other properties of each protein being determined by the side chains of the amino acids and there chemical attachments: proteins include such specialized forms as collagen for supportive tissue, hemoglobin for transport, antibodies for immune defense, and enzymes for metabolism.

Amino acids: Any of a class of organic compounds that contains at least one amino group, -NH2, and one carboxyl, -COOH: the alpha-amino acids, RCH(NH2)COOH, are the building blocks from which proteins are constructed.

Answer:

Chemical reactions would slow down and even not proceed at all without enzymes.

Explanation:

Enzymes are protein catalysts, meaning they speed up chemical...

Answer:

all sloped parts

Explanation:

Sloped part of the curve  - all      as this would show a change in T   ( or delta T)

  the flat parts would involve no change in Temp

Answer:

By observing chemical reactions, we are able to understand and explain how the natural world works. Chemical reactions turn food into fuel for your body, make fireworks explode, cause food to change when it is cooked, make soap remove grime, and much more.

hope it helps you

Although soils are capable of resisting pH changes, there are some circumstances where the pH of the water can result in alterations.

The texture of soil affects how susceptible it is to the pH of the surrounding water. Smaller soil particles, such as clays and clay loams, have a greater impact than larger, sandier soils. There are more colloids, which are extremely minute particles, in fine-textured soils. Positively charged ions are maintained at these colloids. The cation exchange capacity of a soil refers to its capacity to hold onto these ions. Ions on the colloidal particles trade places with ions in the soil solution. The pH of the soil is less affected by negative ions in the soil solution.

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Answer:

alcohol

Explanation:

alcohol thus, C2H5OH

Answer:

2KOH + H2SO4 > K2SO4 + 2H2O

Explanation:

firstly the order speaks, you can't have something like OKOH so the other two is eliminated. Then check if the remaining reactions balance

The  correctly balanced chemical equation for the reaction of KOH and H₂SO₄ is 2 KOH+H₂SO₄ → K₂SO₄+2 H₂O.

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.

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Answer: An acid is defined with having more [H₃O+] ions, and a base is defined with having more [OH-] ions. On the pH scale, an acid has a lower pH and a base has a higher pH. With this being said, the lower the pH, the more [H₃O+] ions are present and the higher the pH, the more [OH-] ions are present.

Explanation:

I hope this helps!! Pls give brainliest!! :)

Energy cannot be created nor destroyed, but it changes from one form to another. Hence, option C is correct.

Energy is the ability to do work.

In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time.

This law means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.

Hence, option C is correct.

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Answer: Some possible bias in an experiment about how sleep affects mood could be a person's average mood with or without sleep, how people are acting in the experiment compared to how they actually would in their normal environment, or even how the person collected the data for the experiment interprets their moods.

Explanation:

1. A person's mood could be relatively different depending on other factors than just sleep, so it could affect experiment. For example if an emotional crisis had occurred recently, it could affect your mood and environmental factors could affected your mood, like weather.

2. A person could also change their mood around strangers or even when participating in the experiment. For instance if they aren't comfortable with the person taking down the analysist or the other test subjects, they make act differently than they usually do at home where they're comfortable.

3. A person collecting the data will have to know how to specify and determine a persons mood with their instruments. For example, if they're doing it just by talking with the test subjects, they'll have to know how to properly understand their different stages of each of their moods with out the data collectors mood changing as well. Also, if the data collectors mood is changed at all it can slightly affect the experiments results as well.

Answer:

-1071 Joules

Explanation:

The Joule was introduced as the SI unit for energy in 1925.  One calorie is equal to approximately 4.184 joules(J).  This is a conversion factor that we can write two ways:

(1cal/4.184J) or (4.184J/1cal)

(265 cal)*(4.184J/1cal) = 1071 J

Since the energy is leaving the system, it should be written with a minus sign:  -1071J

Answer:

1,108.76 joules

Explanation:

There are 4.184 joules per calorie

4.184 x 265 = 1,108.76

The given reaction Mg + O₂ → MgO is a type of Synthesis reaction. Hence option (1) is correct.

Synthesis reactions are reactions that occur when two different atoms or molecules interact to form one molecule or compound.

It is also known as combination reaction

In the given reaction Mg and O combines with each other to form one product i.e, MgO. Hence, The given reaction Mg + O₂ → MgO is a type of Synthesis reaction. Thus, option (1) is correct.

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Answer:

A

Explanation:

I think it's A. There are good answer for A.

Answer:

temporary changes are the changes which are there only for a short period if time generally temporary changes are reversible permanent changes are the changes which remain to for longer time and are not reversible

Explanation:

hope it is helpful for

Answer:

0

Explanation:

they cancel each other out (ex: 1 positive and 1 negative cancels, making it neutral or a charge of 0)

Answer:

This is not oxidation as it gain electron .

Oxidation reaction means addition of oxygen or removal of hydrogen

or in other words loss of electrons

Mg ----> Mg²+ + 2e

this is oxidation reaction as Mg loss 2e to become +2

Sn³+ -----> Sn4+ + 2e

this is oxidation reaction as it losses electrons

similarly other are also oxidation.

Answer:

protons and neutrons have different charges but they have approximately the same mass

MgSo4 will be formed