please answer these 7 questions its for a test

Answer:

it disappeared loll jk

it obviously dried

well you may Mark me as brainliest

Answer:

Because you can see the stars everynight pretty much, but the planets you need a telescope for. Plus, the planets are moving everynight making night and day so they all move! :)

Explanation:

Hope this helps! Brainliest plz?

Answer:

Explanation:

In order to have a full shell it needs eight. It is easier to gain three electrons instead of losing five. Therefore phosphorus tends towards P3−

Answer:

Although PPT was initially prepared from terephthalic acid (TPA) and 1,3-propanediol (PDO) in the 1950s, it has been mainly synthesized by transesterification of PDO with dimethyl terephthalate (DMT) similar to poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT).

Explanation:

Answer: a. 249.5 g/mol

b. 1.996 g

c. Measure 1.996 g of [tex]CuSO_4.5H_2O[/tex] and dissolve in water until the volume is 400 ml

Explanation:

Molar mass is the sum of atomic masses of all the elements present.

Thus molar mass of [tex]CuSO_4.5H_2O[/tex] = 1(63.5)+1(32)+4(16)+5(18) = 249.5 g/mol

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

To calculate the number of moles for given molarity, we use the equation:

[tex]\text{Molarity of the solution}=\frac{\text{given mass of solute}\times 1000}{\text {Molar mass of solute}}\times \text{Volume of solution in ml}}[/tex]

[tex]0.02mol/L=\frac{x\times 1000}{249.5g/mol\times 400}[/tex]

[tex]x=1.996 g[/tex]

c. We need to measure 1.996 g of [tex]CuSO_4.5H_2O[/tex] and dissolve it in water to make the volume 400 ml.

Answer:

no it's not

Explanation:

because H2+O2=H2O

so the balanced form is

H2 +O2=2H2O

Salt suitable for sprinkling on food at meals.

Answer:

the atomic number of the atom can be determine through the number of protons in the nucleus

The protons are usually the atomic number.

Answer:

2200 degrees Fahrenheit

Explanation:

700°C to 1300C where's my points at

Answer:

In a solid, they're really close together and vibrate a LITTLE, in a liquid they're kinda close together but change movement because water will change shape depending on the container they're in. For gas they are spread far from each other and vibrate A LOT

Explanation:

Answer:

C8H20P4F8

Explanation:

Molecular formula is based off a ratio of the molecular formula's molar mass divided by the empirical formula's molar mass.

The molar mass of the empirical formula C2H5PF2 is 98.02g. We find this by adding the molar masses of all elements in the formula, multiplied by their subscripts.

2(12.01) + 5(1.01) + 30.97 + 2(18.99) = 98.02

We then divide the molecular molar mass by the empirical molar mass.

392.16/98.02 = 4

This tells us that the molecular formula has 4 times the mass of the empirical formula. Because mass comes from the elements in the formula, we multiply all the subscripts by 4 to get the molecular formula.

2x4 = 8

5x4 = 20

1x4 = 4

2x4 = 8

So the molecular formula is C8H20P4F8

Answer:

A

Explanation:

Just took the quiz

The irregularity of the chart means that, monitoring concentrations of pollutants has been ineffective.

The EPA is the environmental protection agency which takes care of the set limits of pollutamts that are released into the environment. The chart shows the monitoring of the concentrations of pollutants over a period of time.

We can see tat the chart is so irregular. The irregularity of the chart means that, monitoring concentrations of pollutants has been ineffective.

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Answer:

13.7 degrees.

Explanation:

Answer: B. 0.36 moles

Explanation:

According to ideal gas equation:

[tex]PV=nRT[/tex]

P = pressure of gas = 260 mm Hg = 0.342 atm         (760 mm Hg= 1atm)

V = Volume of gas = 31.0 L

n = number of moles = ?

R = gas constant =[tex]0.0821Latm/Kmol[/tex]

T =temperature =[tex]87^0C=(87+273)K=360K[/tex]

[tex]n=\frac{PV}{RT}[/tex]

[tex]n=\frac{0.342atm\times 31.0L}{0.0821L atm/K mol\times 360K}=0.36moles[/tex]

Thus the moles of gas present are 0.36

Answer:

225

Explanation:

I hope it helps

Answer:

Elements are in the same amounts but they are different compound. So it is False:)

Explanation:

Good luck and stay safe!!

Sodium chloride has high melting point because it has strong ionic bonds, whereas paraffin wax melts easily because of weak intermolecular forces

There are strong electrostatic attractions between the positive and negative ions, and it takes a lot of heat energy to overcome them.

Ionic substances all have high melting and boiling points means NaCl has high melting point and molecular means paraffin wax compounds are generally quite low compared to those of ionic compounds because the energy required to disrupt the intermolecular forces between molecules is far less than the energy required to break the ionic bonds in a crystalline ionic compound that's why sodium chloride, an ionic compound have high melting point whereas paraffin wax, a molecular compound, melts easily.

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Answer:

C

Explanation:

Answer:

Rainforest

Explanation:

rainforests tend to have high humidity, explaining why you always sweat there. and including high temps.

Answer: The empirical formula of vitamin C is [tex]C_3H_4O_3[/tex]

Explanation:

Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.

Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.

The molecular formula of Vitamin C is [tex]C_3H_4O_3[/tex].

The simplest whole number ratio will be 3: 4: 3 , and thus empirical formula will be [tex]C_3H_4O_3[/tex].

Answer:

103 so easy so free dogwater

Explanation:

Mass percentage does not have any unit as numerator and denominator contains the same unit. The mass of  rock is 2.56×10⁶g when it contains 1.0 x 10³ kg of iron in it.

Mass percentage represents the the percentage of each element that is making a particular compound.

Mathematically,

Percentage of mass = (component’s mass ÷ total mass) x 100%

Percentage of mass of ferric oxide is =  78% by mass in rock

From this we can interpret the following

100 g of rock contains = 78gram ferric oxide

(100÷78)g of rock contains= 1 gram of ferric oxide

mass of iron in rock =1.0 x 10³ kg = 1.0 x 10⁶ g

(100÷78)×1.0 x 10⁶ g of rock  = 1.28×10⁶g of ferric oxide

now 1 mole of ferric oxide contains 2 atoms of iron, so the total mass of iron is 1.28×10⁶g ×2=2.56×10⁶g of iron.

Therefore the mass of  rock is 2.56×10⁶g when it contains 1.0 x 10³ kg of iron in it.

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Answer:

The correct answer to your Question is B.

Explanation:

Hope you have a great day :)

The substance from the options that will dissolve most rapidly is : ( B ) Powdered sugar in hot water.

Increase in temperature, state of solute and volume will determine the rate at which solubility occurs. The powdered sugar is in less solid state when compared to sugar cubes and therefore will dissolve most rapidly in hot water than a sugar cubes in hot water.

Hence we can conclude that The substance from the options that will dissolve most rapidly is : ( B ) Powdered sugar in hot water.

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Answer:

2 electrons will move from magnesium to oxygen

Explanation:

Valence electrons have higher energy than the electrons in inner orbits, valence electrons participate in chemical reactions. A certain element's chemical characteristics can also be determined by the quantity of valence electrons that are present. The correct option is C.

The amount of electrons an atom must gain or lose in order to achieve the electrical configuration of the nearby noble gas or inert gas is known as valence. "Valence electrons" are described as "non-filled electrons in the outer shells."

The s and p electrons in the outermost shell are valence electrons. Core electrons are those found in the inner shell. Valence electrons are minuscule subatomic particles that we come across as we examine and investigate an element's atom. We can trace the valence electrons and forecast the sorts of bonds with the aid of Lewis structures.

'Mg' has two valence electrons and 'O' has six valence electrons. So 'Mg' loses its two electrons to 'O' to attain the octet.

Thus the correct option is C.

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Answer:

the final reaction

Explanation:

a chemical reaction is caused from the two reactants

Answer:

yes

Explanation:

pp

Explanation:

The enzyme 's active site binds to the substrate. Increasing the temperature generally increases the rate of a reaction, but dramatic changes in temperature and pH can denature an enzyme, thereby abolishing its action as a catalyst. ... When an enzyme binds its substrate it forms an enzyme-substrate complex.

Answer:

chlorine

General Electronic configuration of the group number 2 elements is, . General Electronic configuration of the group number 17 elements is, . From this we conclude that the chlorine is the element which has the greatest number of valence electrons available for bonding. Hence, the correct option is, Chlorine

Explanation:

Explanation:

group 18

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In modern times, we know that the elements in a given group (also known as a family or column) have the same number of valence electrons, with ground state configurations having a consistent pattern, for instance:

F 1s2 2s2 2p5, Cl 1s2 2s2 2p6 3s2 3p5, Br 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p5, etc.

Of course, the ground state configurations play a major role in determining how an element reacts and what compounds it forms. Thus, the elements in a given group have similar properties.

The structure of the table also predicts how the properties vary. For instance, atomic radius increases down a group as does metallic character.

Explanation:

Answer:

4s, 3d, 4p

Explanation:

(3d,4s,4p) and (4p, 3d, 4s) both are decreasing energy, while (4s,4p,3d) is incorrect order it should be (4s,3d,4p).