please help me .........
solve it.​

Answer:

The last one

Explanation:

Charges are balanced in a redox reaction

Answer:

Some signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color change, formation of a precipitate, formation of a gas, odor change, temperature change.

I think its the substances that sublimes

Considering the definition of enthalpy of reaction, the correct answer is option C. a reaction with a negative enthalpy indicates that the reaction is exothermic.

The enthalpy of a chemical reaction as the heat absorbed or released when chemicals are transformed into a chemical reaction and it occurs at constant pressure.

The enthalpy is an extensive property, that is, it depends on the amount of matter present.

Finally, it must be taken into account that:

In summary, a reaction with a negative enthalpy indicates that the reaction is exothermic.

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C. NaOH

C. Cu (OH)

A. HCl

Answer:

A ball is thrown straight up from a rooftop 320 feet high. The formula below describes the ball's height above the ground, h, in feet, t seconds after it was thrown. The ball misses the rooftop on its way down and eventually strikes the ground. How long will it take for the ball to hit the ground? Use this information to provide tick marks with appropriate numbers along the horizontal axis in the figure shown.

h=-16t^2+16t+320

Resources found in lithosphere: gold and iron etc

Resources found in atmosphere: Water vapor, gases etc.

Answer: A the location of atoms, groups, or ions relative to one another and the number, type, and location of covalent bonds

Explanation: I just took the assessment and in my notebook molecular structure has a definition that is literally answer A. Also I got it right lol.

Answer:

The SI base units are the standard units of measurement defined by the International System of Units (SI) for the seven base quantities of what is now known as the International System of Quantities: they are notably a basic set from which all other SI units can be derived.

Answer:

okay so basically what you are being tested is if you know the difference between simple and fractional distillation and okay you can evaporate the mixture but you won't obtain water so you will use simple distillation to obtain both salt and water

Answer:

If a body is accelerated by 10m/s^2, it means that the body's speed (or velocity to be precise) is increasing by 10m/s every second. That is, if the initial ...

Answer:

250 minutes

Explanation:

60 seconds = 1 minute

15000 secods = 15000 / 60

1500 secons = 250 minutes

The problem is solved by balancing the reaction equation as shown below. The stoichiometry of the reaction is now applied in solving the question.

The balanced reaction equation is:

SiO2 + 6HF → H2[SiF6] + 2H2O

Using stoichiometry

The amount of silicon dioxide reacted = 12.5 g/60.08 g/mol = 0.21 mole

1 mole SiO2 yields 2 moles of H2O

0.21 mole of SiO2 yields 0.21 * 2/1 = 0.42 moles of H2O

The amount of HF reacted = 24.6 g/20.01 g/mol = 1.23 moles of HF

6 moles of HF yield 2 mole of H2O

1.23 moles of HF yields 2 * 1.23/6 = 0.41 moles of H2O

Hence HF is the limiting reactant.

Theoretical yield of H2O = 0.41 moles of H2O * 18 g/mol = 7.38 g

The percentage yield of the water is = actual yield/theoretical yield * 100

Hence;

% yield = 2.50 g/7.38 g * 100 = 33.9%

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Answer:

The correct answer is - D.  the energy stored inside the center of an atom.

Explanation:

Each atom has a small center in it called the nucleus and the energy that holds the nucleus or center of the atom together in the atom is known as nuclear energy.

It is the energy that is stored in the center of the atom and normally does not come out, however, in some radioactive atoms the sends some part of the energy as radiation.

Thus, the correct answer is - D.  the energy stored inside the center of an atom.

Answer:

Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They may be used to treat these symptoms in patients with peptic ulcer, gastritis, esophagitis, hiatal hernia, or too much acid in the stomach (gastric hyperacidity).

Answer:

wow it's a very nice question

Explanation:

an acid will give away a proton and become a conjugate base.

A base will accept a proton and become a conjugate acid.

Answer:

The change from a liquid phase to a gaseous phase occurs when the vapor pressure of the liquid is equal to the atmospheric pressure exerted on the liquid.

Explanation:

Boiling is a physical change and molecules are not chemically altered during the process.

Answer:

sublimation

Explanation:

Answer:

62L

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tysm.

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hope it help

The Sun radiates sunlight (visible)  photons

Photons from the Sun strike Earth and become infrared photons.

Earth radiates infrared photons into the atmosphere

CO2 in the atmosphere absorbs infrared  photons.

CO2 in the atmosphere emits infrared photons back toward Earth.

Certain gases are known to contribute towards global warming. Such gases are called greenhouse gases. The infrared rays from the sun are absorbed by these gases as they are re-emitted from the earth and re-emitted.

The sun radiates photons to the earth which is re-radiated into outerspace from the earth's surface. CO2 and other greenhouse gases absorbs these gases and re-emit them to the earth thereby causing a gradually rise in the temperature of the earth called global warming.

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The final temperature of the water, T2 = 38.57°C

Temperature can be defined as a measure of the degree of hotness or coldness of a physical object (body). Thus, it is measured with a thermometer and its units are degree Celsius (°C), Fahrenheit (°F) and Kelvin (°K).

A calorie refers to the amount of heat required to raise the temperature of a gram of water by one (1) degree Celsius (1°C).

Given the following data:

The specific heat capacity of water is 4.2 J/g°C.

To find the final temperature of the water (T2):

Mathematically, the quantity of energy (heat capacity) is given by the formula;

[tex]Q = mcdt[/tex]

Where;

Substituting the values into the formula, we have;

[tex]420 = 3.5 \; * \; 4.2 \; * \; dt[/tex]

[tex]420 = 14.7 \; * \; dt\\\\dt = \frac{420}{14.7}[/tex]

Change in temperature, dt = 28.57°C

Next, we would solve for the final temperature by using this formula;

[tex]dt = T2 - T1[/tex]

[tex]28.57 = T_{2} - 10\\\\T_{2} = 28.57 \; + \; 10\\\\T_{2} = 38.57[/tex]

Final temperature, T2 = 38.57°C

Therefore, the final temperature of the water, T2 is equal to 38.57°C

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Answer:

Metal

Element: Calcium

Valency: 2

Explanation:

To find the element, let's use the periodic table. (Look below)

We already went past 3 shells, just need the 2 electrons after it.

Just skip to the 4th row and count 2 to the right

We end up at Calcium.

Calcium is a metal and we're also on the alkaline earth metals column.

Calcium will need to lose 2 electrons to reach stability, so the valency is 2.

Answer:

The given statement is False.

The organisms adapt as a result of competition for resources. Different places have different organisms suited for that particular places.

The animals living at a particular place compete for the resources available and the nature selects the organism that has won the competition for resources.

The organisms are evolved as a result of competition for resources

Answer:

I just wanted to say the other person is totally right.

this statement is false.

Answer:

Sedimentation and decantation

Explanation:

Sedimentation and decantation: Mixture is kept undisturbed for some time. After some time, sand being heavier and insoluble in water, settles down at the bottom of container. Now, water is poured into another container to separate it from sand.

Answer:

evaporation or destillation

Explanation:

When sand is added to water it either hangs in the water or forms a layer at the bottom of the container. Sand therefore does not dissolve in water and is insoluble. It is easy to separate sand and water by filtering the mixture. Salt can be separated from a solution through evaporation.

Answer:

The IUPAC structure only shows bond pairs and lone pairs. In the flouromethane structure above, there is only one bond pair and three lone pairs of electrons. Therefore there is one electron remaining, but since it doesn't not make up a pair, it is ignored in the structure but theoretically it is present.

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Answer:

therefore there is one electron remaining , but since it doesn't make up a pair . It is ignored in the structure but theoretically it is present .

Answer:

Age. ...

Residency. ...

Residence and Physical Presence.

Good Moral Character.

Attachment to the Constitution.

Language.

U.S. Government and History Knowledge.

Oath of Allegiance.

These are some requirements for obtaining citizenship .

I guess ensuring that you don't suck the insects or specimen collected by ensuring there is a net in the pooter

Formation of small pieces of iron shavings is a physical change whereas burning of pieces of iron shavings is chemical change.

Formation of small pieces of iron shavings is an example of physical change because it can be changed again into nail while on the other hand, burning of pieces of iron shavings on the flame is an example of chemical change because it can't change again into its original shape. Physical change is a change in matter which does not change the chemical properties of the matter whereas chemical change is a change in matter which change the chemical properties of the matter.

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