Obi is trying to determine if a powdery, solid substance is an element or a compound. After recording some observations, he strongly heats a sample of the solid over a burner flame. After fifteen minutes, he turns off the flame and allows the sample to cool. He records his final observations in the data table.

Which is the best explanation of his results?

The heating changed some of the sample to gas, causing the mass to decrease without breaking down the sample. Therefore, the original sample is a compound.
The appearance stayed the same, showing that the sample was not broken down by heating. Therefore, the original substance is an element.
The mass decreased during heating and some of the impurities escaped. Therefore, the original substance is an element.
The chemical reaction with acid changed, showing that the sample was broken down by heating. Therefore, the original substance is a compound

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\[/tex]

From the question

mass = 12 g

volume = final volume of water - initial volume of water

volume = 18.5 - 14 = 4.5 mL

So we have

[tex]density = \frac{12}{4.5} \\ = 2.66666666...[/tex]

We have the final answer as

Hope this helps you

Answer:

Endothermic

Explanation:

Exo is outside so exothermic would be outside the body

The carbohydrates are break down into glucose. Then glucose combines with oxygen in the cells and provides energy. Hence, digestion is an exothermic process.

Food digestion produces heat. This happens as a result of the organism releasing heat during meal digestion. A process that releases heat is exothermic.

Heat is released during an exothermic reaction, raising the temperature of the immediate environment. The environment is cooled through an endothermic process that absorbs heat.

Glucose is created by the breakdown of these carbs. In the cells of our body, this glucose interacts with oxygen to produce energy. So, the process of digesting is exothermic.

Chemical processes involved in food digestion disassemble large food molecules into smaller, more manageable "building block" components.

Thus, Human body uses the energy provided from food digestion is exothermic process.

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Answer:

See explanation

Explanation:

It is important to know the properties and chemical formulas of ionic and molecular compounds because, knowledge of the properties of a compound aids you in deciding how to use the compound, how to store it and how dangerous it can be. Knowledge of its formula is the first step towards identifying its properties since most chemicals occur in groups having similar chemical/physical properties.

Knowledge of the chemical properties and formula of bleach and drain cleaner will help you to decide which product is a better cleaning agent based on its chemical composition. This will help you as the user to make  better decision.

Learning about atomic structure has made me to understand that all matter in the universe are composed of atoms. indeed, certain occurrences in nature can only be explained on the basis of atoms involved.

Answer:

The sum of potential energy and macroscopic kinetic energy is called mechanical energy and stays constant for a system when there are only conservative forces (no non-conservative forces). The more mass a moving object has, the more kinetic energy it will possess at the same speed.

Explanation:

Answer: Mechanical energy

Explanation: The more mass a moving object has, the more kinetic energy it will possess at the same speed

Answer:

12 meters

Explanation:

Density = Mass/Volume but it can also be rearranged to:

Mass = Volume x Density

Given in the question:

Volume - 44.9 cc

Density - 19.3 g/cc

Calculation

Mass = Volume x Density

= 44.9 x 19.3

= 866.57 g

Explanation:

The Committee has already adopted general comment No. ... Non-discrimination - education must be accessible to all, especially the most ... developmental strategy for its school system.as poverty and discrimination and to provide education of sufficient quality, in a manner that ensures children can benefit from it.

Answer:

Average atomic mass of moorium is 39.844 amu.

Explanation:

Given data:

Atomic mass of moorium-36 = 35.978 amu

Relative abundance of  moorium-36 = 1.32%

Atomic mass of moorium-38 = 37.963 amu

Relative abundance of  moorium-38 = 3.25%

Atomic mass of moorium-40 = 39.962 amu

Relative abundance of  moorium-38 = 95.43%

Solution:

Average atomic mass moorium = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)+ (abundance of 3rd isotope × its atomic mass)  / 100

Average atomic mass of moorium = (1.32×35.978)+(3.25×37.963)+(95.43×39.962) /100

Average atomic mass of moorium =  47.491 + 123.380 +3813.574  / 100

Average atomic mass of moorium = 3984.445 / 100

Average atomic mass of moorium = 39.844 amu

one substance becomes two new substances

Answer:

B) It will be lower, because the temperature of the room-temperature water will not increase as much.

Explanation: I took the test

Answer:

atomic number if it's a answer

Answer:

I think its the average atomic mass.

Explanation:

yes it is a element.

Answer:

Slaves were in high demand in the southern colonies because they were the main source of labor. ... Bacon and others colonists wanted to take the Natives land.

Explanation:

HOPE THIS HELPED ❤✨

Answer: The chemical is disrupted, also most likely causing an explosion.

Explanation:

Answer: 2 kg

Explanation:

Answer:365 days, 5 hours, 59 minutes and 16 seconds.

Answer: 20

Explanation: I’m in your class.

Answer:

Water that falls from the clouds.

Explanation:

Answer:

no

Explanation:

Answer:

0.097 g/cm3

Explanation:

divide mass over volume

Answer:

Option C: Warm temperatures will replace cold temperatures.

Explanation:

In a weather map, a warm front is depicted with a red line and red semi circles while a cold front is depicted with a blue line and blue triangles.

Now, we are told that the map shows a blue line with triangles approaching a red line with semi-circles. This means that the cold front is approaching the warm front.

Now a warm front is simply defined as the transition zone where warm air mass gradually replaces a cold air.

Thus, it means the weather map depicts the fact that warm temperature is replacing cold temperature.

Thus; Option C is correct.

Answer: 1: A cold front moved into the area. 2: It would actually be A. A significant drop in temperature will occur across the area. 3: Movement of large air masses. 4: “A Strong Cold Front Threatens the Region”. 5: a meeting of two air masses with major differences in temperature and moisture.

Hope you got 100 because of this!

Answer:

i think the grass population would decrease

Explanation:

Answer:

The Coyote population would decrease

Explanation:

Answer:

D

Explanation:

Melting of ice is a physical change as there no new compound is forming only state is changing So Option D is correct option. For second question Option D is correct option as combustion reaction is taking place.

Chemical change is a reaction in which breaking and forming of new bonds take place. One molecule completely converted to totally different molecule. The number of atoms remains same

One famous example of chemical change is the rusting of iron. The color, odor and arrangements of atoms in products are very much different from reactant. Chemical change are mostly irreversible in nature.  Physical change is just opposite of chemical change. Phase change is an example of physical change.

Thus option D  is correct option in both cases.

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Answer:

23, B

Explanation:

The mass of an atom is determined by the number of Protons + Neutrons. Here, if we assume the units is AMU (Which means the mass unit for a proton and neutron would be basically 1), the answer would be 11 + 12 = 23 AMU, which is B.

Answer:

B) 23

Explanation:

Relative Mass = number of protons + number of neutrons

Relative Mass = 11 + 12

Relative Mass = 23

Answer:

Two molecular properties that could be used to separate a substance from a mixture are - Filtration and Chromatography .

Explanation

Molecular property -Molecular properties include the chemical properties, physical properties, and structural properties of molecules, including medicines. Typically, molecular properties do not include a chemical compound's pharmacological or biological properties.

Usually, filtration is an imperfect operation. On the feed side of the filter or embedded in the filter media, some fluid remains and some tiny solid particles make their way through the filter.

example - Filters containing fibers that trap particulates are used by many aquariums.

Chromatography can be analytical or preparatory. Preparative chromatography is intended to isolate the components of a mixture for subsequent use and is therefore a method of purification. Analytical chromatography is usually conducted with smaller quantities of material and is intended to assess the presence of analytes in a mixture or to measure their relative proportions. Both are not limited to each other.

An example of chromatography is when a chemical reaction is used to separate each of the various sized molecules on a piece of paper in a liquid compound into their own pieces.

Hence , the answer is filtration and chromatography .

Answer: Explanation:

You can change an object's state of matter by adding or removing thermal energy. When you add thermal energy to an object, these things can happen: Particles move faster (increased kinetic energy). Particles get farther apart (increased potential energy).

Answer:

D)a zero net force causes no change in an objects motion.

A zero net force causes no change in an object's motion. This statement is true about zero net force. Therefore, option D is correct.

An item that is originally at rest and has no net forces operating on it will stay at rest. If it is going, it will keep moving straight forward at a consistent speed. Forces are "pushes" or "pulls" on the object, and they are vector numbers, just like acceleration and velocity.

A automobile travelling at 50 mph on a highway continually has a net force of zero even though it is moving, since there is no acceleration and the speed is constant.

The total net force acting on an object as it moves at a steady speed is always zero. If you apply force, friction or another force (or several forces) will balance it out.

Thus, option D is correct.

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Answer: the 1st answer is neutrons and i think the 2nd is nucleus

Explanation:

The mass of an atom is found by adding its protons and neutrons. The electric charge of an atom is found by adding the charges of its protons and electrons.

The atomic mass of an element is the total number of protons and the number of neutrons carried by one atom of that element. The atomic mass of an element is usually expressed in grams or a.m.u.

The atomic mass of an element = No. of protons + No. of neutrons

or

The atomic mass of an element = No. of electrons + No. of neutrons

The atomic number gives us information about how many protons are inside the nucleus of the atom. Elements are recognized by the number of protons in the nucleus. Neutrons are uncharged elementary or subatomic particles that are stable when bound in an atomic nucleus.

As the electrons and protons are charged particles in an atom, therefore, the sum of the charge carried by them is equal to the electrical charge of the atom.

For a neutral atom, the number of protons present in an atom is always equal to the number of electrons.

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Answer:

hydrogen is a non-metal, and has one valence electron.

Explanation:

Hope this helps!!

Hydrogen shows properties of both metals and nonmetals. However, hydrogen is placed with the alkali metals since it contains one valence electrons.

Hydrogen is the first element in the periodic table. It has only one electron and it is the valence electron of hydrogen. Therefore, hydrogen is placed in the first group of periodic table.

Hydrogen needs one more electrons to become stable. The 17th group elements halogens also have a valency of  one. Hence, hydrogen shows some chemical similarities with halogens also.

Mostly hydrogen forms covalent bonds like non-metals and in rare cases, hydrogen forms ionic bonds by donating its electron. Therefore, hydrogen is mostly considered as a non-metal.

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