Help me this, I only have 10 minutes to answer!!!!

Answer:

Explanation:

2Ca    +    O₂   =    2CaO

80 g     32 g         112 g

given amount of Ca = 7.75 g

it will require oxygen =  32 x 7.75 / 80 = 3.1 g

but available oxygen = 2.44 so oxygen is the limiting reagent .

32g oxygen reacts with calcium to give 112 g of calcium oxide

2.44 gram of oxygen reacts with calcium to give 112 x 2.44 / 32 of CaO .

= 8.54 gram .

Theoretical yield of CaO = 8.54 gram.

Answer:

The frequencies of light that an atom can emit are dependent on states the electrons can be in. When excited, an electron moves to a higher energy level or orbital. When the electron falls back to its ground level the light is emitted.

Answer:

A Light is produced when an electron moves from a higher to a lower energy level.

Explanation:

Answer:Explanation:

The statement that best describes the people of the Mississippian Period is that they were farmers who used simple tools to grow their food in small gardens. They would also fish and gather food such as muscles, in order to create a large enough food supply in addition to produce from these gardens and farms.

Answer:Within the flower, sperm cells are produced by pollen at the tips of stamens, while egg cells develop in ovules, tiny structures embedded in the ovary at the base of the pistil.

I didn't realize the person up top had the same answer give them the brainliest! :)

Answer:

2044

Explanation:

Answer: Lithium and Ethanol

Explanation: As lithium and ethanol both have a density of under

1.000g/ml, they can be supported by the water. Blood and Magnesium are denser than the water and will therefore sink as the water can not support it them.

Answer:

1

Explanation:

Answer:

d. Sulfur and chlorine.

Explanation:

A covalent bond is formed by two non-metals with similar electronegativities. As a consequence, they share one or more pairs of electrons between their nuclei.

Which of the following pairs of elements is most likely to share one or more pairs of electrons between  their nuclei?

a. Lithium and iodine. NO. Lithium is a metal and iodine a non-metal.

b. Sodium and lead. NO. Both sodium and lead are metals.

c. Copper and oxygen. NO. Copper is a metal and oxygen is a non-metal.

d. Sulfur and chlorine. YES. Both  are non-metals.

Answer:

Argon {Ar}

Explanation:

The noble gas used for a condensed electron configuration is the one before the element which you are configuring.

In this case, the element (Mn) is manganese

The noble gas that is before this element is Argon which is the row above it

so your configuration would be {Ar} 3d^5 4s^2

Answer: googles, fire extinguisher, fire blanket

Explanation:

Answer:

yes yes it does

Explanation:

Answer : The number of grams of gold Bob take from the aliens will be 0.5.

Explanation :

As we are given that:

1 zygot = 3 trigots

3 trigots = 2 bigots

4 bigots = 1 gram gold

Now we have to determine the number of grams of gold Bob take from the aliens.

The number of grams of gold Bob take from the aliens will be equal to:

[tex]\frac{1\text{ zygot}}{1}\times \frac{3\text{ trigots }}{1\text{ zygot}}\times \frac{2\text{ bigots }}{3\text{ trigots }}\times \frac{2\text{ gram gold}}{4\text{ bigots }}[/tex]

= [tex]\frac{6}{12}[/tex] gram gold

= [tex]\frac{1}{2}[/tex] gram gold

=  0.5 gram gold

Hence, the number of grams of gold Bob take from the aliens will be 0.5.

Answer:

Mass of hydrogen produced is 0.07g.

Explanation:

Given data:

Mass of magnesium = 7.73 g

Mass of water = 1.31 g

Reaction yield = 88.2%

Mass of hydrogen produced = ?

Solution:

Chemical equation:

Mg + 2H₂O     →   Mg(OH)₂ + H₂

Number of moles of water:

Number of moles = mass/ molar mass

Number of moles = 1.31 g / 18 g/mol

Number of moles = 0.07 mol

Number of moles of magnesium:

Number of moles = mass/ molar mass

Number of moles = 7.73 g / 18 g/mol

Number of moles = 0.43 mol

Now we will compare the moles of water and magnesium with hydrogen.

                    Mg            :           H₂

                     1               :            1

                    0.43          :          0.43

                    H₂O          :             H₂

                      2             :              1

                   0.07           :            1/2×0.07 = 0.035

Mass of hydrogen:

Mass = number of moles × molar mass

Mass = 0.035 mol × 2 g/mol

Mass = 0.07  g

Answer: 0.064 grams is the answer

Explanation:

at the end you must multiply 88.2/100*0.073=0.064

Answer:

the marble would hit the floor first because the feather would be effected by air resistance

Answer:

The net force is greater at the second situation as well as the acceleration due to the contribution of the second guy.

Explanation:

Hello.

In this case, since the net force is computed via adding all the exerted forces on a body, for the first situation we can see that the net force equals the force provided by that guy when pulling, whereas in the second situation the net force equals the force of both of the guys pulling the car:

[tex]F_N_1=F_1\\\\F_N_2=F_1+F_2[/tex]

For the acceleration, we can see that applying an extra force (due to the second guy) turns out into a greater acceleration, that is why the car at the second situation reaches the tree whereas the other one does not.

Best regards.

Answer:

a)2

b)12.5

c)1.5

Explanation:

a)

pH = -log [H^+]

pH = -log [0.01]

pH = 2

b)

pOH = -log[OH^-]

pOH = -log [0.035]

pOH= 1.5

But

pH + pOH = 14

pH = 14 - pOH

pH= 14 - 1.5

pH = 12.5

c)

pH = -log[H^+]

pH= -log[0.030]

pH = 1.5

Answer:

Ans : 22.86 gm of Aluminium

Solution,

                        3FeO + 2Al ---> 3 Fe + [tex]Al_{2}O_{3}[/tex]

Given                   3          2                    

Find                    1.27       x

By the given gms of FeO find its mole and put the moles in the find,

                                       [tex]n = \frac{given mass}{molecular mass}[/tex]

                  Given mass of FeO is 91.8

                   Molecular mass of FeO is 71.8

                                         n = [tex]\frac{91.8}{71.8}[/tex]  

                                         n = 1.27 moles of FeO  

Now solve for x,

                            [tex]x = \frac{2 x 1.27}{71.8}[/tex]

                             x = 0.85 moles

These are just moles of Aluminium that we need to react with FeO, so to find Grams of Aluminium we need,

                                Mass = moles x molecular mass

                                Mass = 0.85 x 27(atomic mass of Al)

                                Mass = 22.86 grams of aluminium is what we need

Answer:

Explanation:

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

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

From the question we have

[tex]density = \frac{52.2}{60} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

its S

Explanation:

Answer:

Explanation:

d =

m

V

m = d×V

V =

m

d

DENSITY

Density is defined as mass per unit volume.

d =

m

V

Example:

A brick of salt measuring 10.0 cm x 10.0 cm x 2.00 cm has a mass of 433 g. What is its density?

Step 1: Calculate the volume

V = lwh = 10.0 cm × 10.0 cm × 2.00 cm = 200 cm³

Step 2: Calculate the density

d =

m

V

=

433

g

200

c

m

³

= 2.16 g/cm³

MASS

d =

m

V

We can rearrange this to get the expression for the mass.

m = d×V

Example:

If 500 mL of a liquid has a density of 1.11 g/mL, what is its mass?

m = d×V = 500 mL ×

1.11

g

1

m

L

= 555 g

VOLUME

d =

m

V

We can rearrange this to get the expression for the volume.

V =

m

d

Example:

What is the volume of a bar of gold that has a mass of 14.83 kg. The density of gold is 19.32 g/cm³.

Step 1: Convert kilograms to grams.

14.83 kg ×

1000

g

1

k

g

= 14 830 g

Step 2: Calculate the volume.

V =

m

d

= 14 830 g ×

1

c

m

³

19.32

g

= 767.6 cm³

The mass of rock is 10 g.

We have sample of rock.

We have to determine its mass.

The density and mass of body are related as follows -

D = M / V

where -

V -  volume of the body.

M - mass of the body.

D - density of the body.

According to the question →

Using the formula discussed above -

D = M / V

M = D x V

M = 2.5 x 4 = 10 g

Hence, the mass of rock is 10 g

To solve more questions on Mass - Density Relation, visit the link below-

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Answer:

1. c

2. d

3. c

4. d

5.

6. a

7. a

8.

Answer:

Explanation:

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

[tex]a = \frac{f}{m} \\ [/tex]

where

a is the acceleration

f is the force

m is the mass

From the question

f = 20 N

m = 5 kg

We have

[tex]a = \frac{20}{5} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

100.5 ≈ 101

Explanation:

Km for S1 = 2.0 mM

Km for S2 = 20 mM

Given that : S1 = S2 =  hence Vmax for either S1 or S2 can represent

The Vmax can be calculated using the data Given and equation below

Vo = Vmax [s] / ( Km + [s] )  ------ (1)

Vo = 0.5

[s] = 0.1 mM

km = 20 mM

making Vmax subject of  equation 1

Vmax = 0.5 ( 20.1 mM) / (0.1 mM )

         = 100.5 ≈ 101

Answer:

the answer is D

Explanation:

hope it helps

Answer:

"What always forms between two large air masses of different moisture and air temperature?"

Explanation:

When a cold air mass replaces a warm air mass the boundary between the two air masses is called a cold front. ... Fronts form at the boundary between air masses of different temperatures and moisture. Warm air always slopes upward over colder air.

The boundary between two air masses of different density such when it can not move called “stationary” “warm” when warmer air replaces cooler air.

The density  can be defined as  the mass per unit volume which means that it is the ratio between mass and volume, that means the object has  the  stuff  in a unit volume.

Density is determined by the matter where it shows how the matter is tightly crammed together and  it was put forwarded  by the Greek scientist Archimedes

To calculate the density of an object, the mass (m) can be divided by the volume (v)

Density = Mass/Volume

The different units include  SI unit of density which is kilogram per cubic meter (kg/m3) or in cgs unit of grams per cubic centimeter (g/cm3).

Learn more about density, here:

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Answer:

alkali metals

Explanation:

alkali metals only have one valence electron, meaning they are extremely reactive. they are considered the most reactive on the periodic table.

Answer:

The answers are A. and D.

According to the concept of solubility and properties of ionic compounds, magnesium sulfate and sodium nitrate dissolve in water.

Solubility is defined as the ability of a substance which is basically solute to form a solution with another substance. There is an extent to which a substance is soluble in a particular solvent. This is generally measured as the concentration of a solute present in a saturated solution.

The solubility mainly depends on the composition of solute and solvent ,its pH and presence of other dissolved substance. It is also dependent on temperature and pressure which is maintained.Concept of solubility is not valid for chemical reactions which are irreversible. The dependency of solubility on various factors is due to interactions between the particles, molecule or ions.

Learn more about solubility,here:

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Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

From the question we have

force = 0.5 × 3

We have the final answer as

Hope this helps you