A spoon. A beaker partially filled with liquid. A stirring rod. A graduated cylinder. Distilled water in a spray bottle. Which of the following tools could have become cross-contaminated during the experiment if you had not cleaned them carefully between successive tests? Spoon Beaker Stirring Rod Graduated Cylinder Distilled water in spray bottle.

Answer:the first one

Explanation:

Answer:

Ribosomes are found in both cells

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1.ans: observations, questions, hypothesis, methods and results are the five components of scientific method.

2.ans: written account of object.

3.ans: sry I didn't get

hope my 2 answers can help you ࿐❤

Answer:

1) Sience involves six kinds of components:

• Problems

• Attitudes

• Methods

• Activities

• Conclusions

• Effects

2) Knowledge is information or information that is known or realized by someone.

3) Science form:

• Direct knowledge (direct)

• Indirect knowledge (mediated)

• Sensory knowledge (perception)

• Conceptual knowledge (conceptual)

• Particular knowledge (special)

• Universal knowledge (universal)

Explanation:

I hope this help :)

The number of mole of ammonium ion, NH₄⁺ in the solution is 0.175 mole

We'll begin by calculating the number of mole of NH₄NO₃ in the solution. This can be obtained as follow:

Volume = 125 mL = 125 / 1000 = 0.125 L

Molarity = 1.40 M

Mole = Molarity x Volume

Mole of NH₄NO₃ = 1.40 × 0.125

Finally, we shall determine the number of mole of ammonium ion, NH₄⁺ in the solution. This can be obtained as follow:

NH₄NO₃(aq) —> NH₄⁺(aq) + NO₃¯(aq)

From the balanced equation above,

1 mole of NH₄NO₃ contains 1 mole of NH₄⁺

Therefore,

0.175 mole of NH₄NO₃ will also contain 0.175 mole of NH₄⁺

Thus, the number of mole of ammonium ion, NH₄⁺ in the solution is 0.175 mole

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Answer:

A positively or negatively charged particle is called an ion.

Explanation:

Ions form when they lose or gain electrons in order to become stable by filling their octet. When an element lose an electron(s), it becomes positively charged and occpanies the symbol (+). When an element gains an electron(s), it becomes negatively charged and occpanies the symbol (-).

Answer:

13.5g

Explanation:

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 138.8g of aluminium is needed to react with 640g of iron oxide.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

Mathematically, the balanced equation can be written as

3Fe[tex]_2[/tex]O[tex]_3[/tex] + 4Al [tex]\rightarrow[/tex] Al[tex]_2[/tex]O[tex]_3[/tex] + 6Fe

number of moles of iron oxide= 640/159.6

                               =4.01

number of moles of aluminium =(4/3)×4.01

                                =5.34moles

mass of aluminium =5.34×26

                               =138.8g

Therefore, 138.8g of aluminium is needed to react with 640g of iron oxide.

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Answer:

Anything that occupies space and has mass is matter but the matter that has specific composition and chemical characteristics is substance

Answer:

Substance: Something that has only 1 atom, for example; Water.

Matter: Made up of more than 1 atom, example; Humans

Explanation:

As said a substance is something that has only 1 atom like water or tin.

Matter is well almost everything in the universe, there's a reason some people say; This is Human Matter. I'm pretty sure it's somewhere in the bible too.

If you were to search it up the other persons answer would come up

Answer:

Neutron is the correct answer.

Answer:

4Fe(s)+3O2(g) ----> 2Fe2O3(s)

Answer:

Explanation:

A substance that flows and keeps no definite shape because its molecules are loosely packed and constantly moving. It takes the shape of its container but maintains constant volume.

Answer:

D. Ethanol

Explanation:

because Propanol, Methanol and Butanol are not safe to consume. soo the answer is Ethanol

Ethanol forms of alcohol can be consumed.

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Answer:

19 electrons, that's what I say

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Explanation:

Hope it helps ^•^

Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons

Answer:

A. Poe

Explanation:

pagmali sorry na Lang

Answer:

Density 0.97 g.cm -3 at 20 °C

Melting point 97.5 °C

Boiling point 883 °C

oxidation states +1, −1 (rare)

Explanation:

Have a nice day

Answer:

eat

Explanation:

eat the dang apples

That means that one mole of cobalt weighs 58.9332 grams (58.9332 g/mol). Based on that information, to convert 2 moles of cobalt to grams, we multiply 2 moles of cobalt by 58.9332.

12.04428152 x [tex]10^{23}[/tex] cobalt atoms are in 2 moles of cobalt.

A mole is defined as 6.02214076 ×[tex]10^{23}[/tex]

of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.

One mole of cobalt is equal to 6.02214076 ×[tex]10^{23}[/tex] atoms.

2 moles of cobalt is equal to 6.02214076 × [tex]10^{23}[/tex]atoms x 2

12.04428152 x [tex]10^{23}[/tex]

Hence, 12.04428152 x [tex]10^{23}[/tex]cobalt atoms are in 2 moles of cobalt.

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Answer:

1) Compound

2) Matter is neither created nor destroyed

3) All of the above

4) Turns litmus paper blue

5) The products often have completely different properties than the reactants.

6) Water freezing into ice

7) You'd wind up with a pH-neutral salt and water.

8) Hydrogen and oxygen molecules (2H2 and O2 )

9) A change on the molecular level

10) Matter has changed size, shape or form

Answer:

Explanation:

Answer:

ANSWER

ANSWER: +1

EXPLANATION

What is the change in oxidation number of bromine in the following re-dox reaction Cl 2 +2HBr 2HCl+Br 2 A -2;0 B) -1;0 C) 0: -1 D) 0;-2

for Cl 2 +2HBr 2HCl+Br 2 , the Cl in Cl2 is reduced from "0" to

"-1" and the Br in HBr is oxidized from "-1" to "0"

So the change in oxidation number is +1

Answer:

Movement in narrow zones along plate boundaries causes most earthquakes. Most seismic activity occurs at three types of plate boundaries—divergent, convergent, and transform. As the plates move past each other, they sometimes get caught and pressure builds up.

Explanation:

Answer:  ground state

Explanation:  The ground state, assuming you’re talking about an electron in an atom. As far as isolated leptons go, the electron is the lowest energy among the electron, muon, and tau particles. Muons and tau particles are unstable. A tau can decay into a muon or electron or other decays, while a muon can decay into an electron and associated neutrinos or gamma rays. Each has a corresponding neutrino, all of which have really, really tiny masses.     P.S not copy pasted

Ground state is the lowest possible energy level that an electron can occupy. When the electron gains energy, it may move to a higher energy level. This is called the exited state.

The ground state is the lowest possible energy level that an electron can occupy within an atom. In this state, an electron is in its most stable configuration, meaning it is closest to the nucleus and has the lowest energy level available to it.

When an electron gains energy from an external source, such as absorbing a photon of light or heat, it can move to a higher energy level. This state is known as the excited state. In the excited state, the electron is located farther from the nucleus and possesses more energy than it does in the ground state. The additional energy is stored by the electron as potential energy in its increased distance from the nucleus.

The excited state is temporary. Electrons in an excited state are not stable, and they tend to return to lower energy levels (closer to the nucleus) by releasing the excess energy in the form of photons of light. This phenomenon is the basis for various processes, including fluorescence and emission spectra.

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Answer:

a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.

mass: 9.1093837015 × 10−31 kg

charges: fundamental physical constant expressing the naturally occurring unit of electric charge, equal to 1.602176634 × 10−19 coulomb.

Explanation:

good luck !<3

Answer:

7 elements

Explanation:

Answer:

There are 7 elements

Explanation:

When the student adds 50 mL of distilled water to each beaker, CaCO3 will not dissolve in water while AgNO3 will dissolve completely in water.

We have to recall that according to the solubility rules, the carbonates of group two elements are insoluble in water. The solubility rules offer a convenient way of predicting the solubility of a compound in water.

When the student adds 50 mL of distilled water to each beaker, CaCO3 will not dissolve in water while AgNO3 will dissolve completely in water. This is because,  the carbonates of group two elements are insoluble in water.

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This problem is providing information about the loss of mass for a reaction 50 °C as a function of the time elapse. Thus, when taking a look at the given graph, we can trace a horizontal line on the y-axis at 0.95 g in order to intercept it with the curve, and hence, figure out the time at which that loss of mass takes place.

Thus, we can see that when the loss of mass hits 0.95 g, the corresponding time on the graph is about 80 seconds, and hence, the rate of reaction turns out to be:

[tex]r=\frac{0.95g}{80s}\\\\r=0.012\frac{g}{s}[/tex]

Which has two significant figures as required.

Learn more:

Answer:

Explanation:

You have given the exact definition of what an atom is. It is the smallest entity that has all the same properties as a bunch of atoms put together.

Answer:

Decreasing the temperature of the copper made the final temperature decrease.

Heat emitted by copper reduces as copper's mass decreases. As the mass of copper lowers due to a decrease in heat gain by water, the final temperature also drops.

The transfer of kinetic energy from an energy source to a medium, an object, or from one to the other is referred to as the creation of heat. The sun is the source of all energies. It is the natural source of solar energy, heat, and light. Thermal energy can move through three different channels: conduction, convection, and radiation.

Therefore, the increase in temperature is always proportionate to the mass of water. Thus, the final temperature will be lower if we increase the water mass. The temperature will be lower in the end. The density reduces as volume grows. Consequently, density drops as temperature rises.

Thus, heat emitted by copper reduces as copper's mass decreases. As the mass of copper lowers due to a decrease in heat gain by water, the final temperature also drops.

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