A student determines the calcium content of a solution by first precipitating it as calcium hydroxide, and then decomposing the hydroxide to calcium oxide by heating. How many grams of calcium oxide should the student obtain if his solution contains 55.0 mL of 0.458 M calcium nitrate?

Answer:

agua

Explanation:

por que estamos en la planeta

i believe the answer would be D. When ordered by atomics mass every eighth element has similar properties.

Answer:

3.36×10²⁶ g

Explanation:

Molar mass ( O2) = 32g/mol

mole(O2) = 1.05×10²⁵mol

Mass(O2) = ?

mole(n)= mass(m)/Molar mass(M)

n×M = m

1.05×10²⁵ mol × 32g/mol = mass

mass= 3.36×10²⁶ g

Answer:

No

Can't understand.

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Answer:

20

Explanation:

Hi there!

We need to find the atomic number of an atom that has 20 protons and 20 neutrons

the atomic number of an atom is equivalent to the amount of protons an atom has, as the number of protons determines what element an atom is.

Since the atom has 20 protons, the atomic number of the said atom is 20

Hope this helps!  

Answer:

Polar molecules occur when there is an electronegativity difference between the bonded atoms. Nonpolar molecules occur when electrons are shared equal between atoms of a diatomic molecule or when polar bonds in a larger molecule cancel each other out

Explanation:

Answer:

True

Explanation:

An atom would carry more protons if positively charged, an equal amount of both protons and electrons if neutral, and more electrons if charged negative.

Answer:

67.5%

Explanation:

Step 1: Write the balanced equation for the electrolysis of water

2 H₂O ⇒ 2 H₂ + O₂

Step 2: Calculate the theoretical yield of O₂ from 17.0 g of H₂O

According to the balanced equation, the mass ratio of H₂O to O₂ is 36.04:32.00.

17.0 g H₂O × 32.00 g O₂/36.04 g H₂O = 15.1 g O₂

Step 3: Calculate the percent yield of O₂

Given the experimental yield of O₂ is 10.2 g, we can calculate its percent yield using the following expression.

%yield = (exp yield / theoret yield) × 100%

%yield = (10.2 g / 15.1 g) × 100% = 67.5%

Answer: The report prepared is a nontestimonial hearsay.

Explanation:

The nontestimonial hearsay can be defined as the expert opinion or statement given casually and not for the purpose of keeping or considering it as record by the government agent or agency. Here the given conclusion provided by the chemical expert is an example of nontestimonial hearsay because it is not the output of experimental and analytical procedures instead it is a casual opinion. Testimonial hearsay include the evidences that are based on detailed and thorough analytic procedures.

Answer:

any 5 ways to prevent earth are:

1.using ( 3R) principles Reduce, reuse, and recycle.

2.Educate yourself

3.Conserve water resources and other natural resources

4.Use long-lasting light bulbs.

5.stop deforestation and start afforestaion

here's your answer hope this will help

Answer:

45

Explanation:

because the number is right

Answer:

-In an closed-end manometer, the gas pressure is equal to the difference in column heights in the two arms of a U tube.

-In an open-end manometer, the gas pressure pushes on the Hg surface on one arm of the U tube and atmospheric pressure gas pushes on the other.

-The gas pressure is directly related to the height of a column of mercury it produces in a U tube.

Explanation:

Manometer is simply an instrument used for measuring the pressure that is acting on a column of liquid.

Now they could either be open ended or closed ended manometers.

However the difference between both of them is that;

Closed - end manometer are those used to measure absolute pressure while open end manometer is used to measure the gauge pressure.

From operation of a closed end manometer, the gas pressure is read from the difference in column heights of the two arms of the U tube being used. While in open end thermometer, the gas pressure will push the mercury surface on one arm of the U tube while the atmospheric pressure gas will push on the other arm.

Lastly, the height of a column of mercury in the U-tube is directly related to the gas pressure.

Thus, the correct options are A, D, E

Explanation:

I did it in steps to help u to understand :)

Answer:

This reaction is exothermic because the system shifted to the left on heating.

Explanation:

2NO₂ (g) ⇌ N₂O₄(g)

Reactant => NO₂ (dark brown in color)

Product => N₂O₄ (colorless)

From the question given above, we were told that when the reaction at equilibrium was moved from room temperature to a higher temperature, the mixture turned dark brown in color.

This simply means that the reaction does not like heat. Hence the reaction is exothermic reaction.

Also, we can see that when the temperature was increased, the reaction turned dark brown in color indicating that the increase in the temperature favors the backward reaction (i.e the equilibrium shift to the left) as NO₂ which is the reactant is dark brown in color. This again indicates that the reaction is exothermic because an increase in the temperature of an exothermic reaction will shift the equilibrium position to the left.

Therefore, we can conclude that:

The reaction is exothermic because the system shifted to the left on heating.

The reaction is exothermic and the equilibrium position shifted to the left hand side.

An exothermic reaction is one in which heat is given out. Hence, the equilibrium position moves towards the left when the temperature is increased in an exothermic reaction.

Given the reaction, 2NO2(g) ⇌ N2O4(g) the appearance of a dark brown gas at high temperature implies that the reaction is exothermic and the equilibrium position shifted to the left hand side.

Learn more about exothermic reaction: https://brainly.com/question/15308590

Answer:

[tex]10 {7}^{2} = [/tex]

Answer:

They are chemically bonded to one another

Answer:

they can be classified as elements

Answer:

C) K

Explanation:

K has an electron configuration of 2.8.8.1

fluorineelement has 9 electrons, and 11 neutrons

Answer:

0, +2

Explanation:

As a pure element, any element or simple compound has an oxidation number of 0. This makes it a lot easier, and can be applied for almost any element or compound that uses one atom, like F2, O3, Zn, Fe, etc. However, in compounds, Zinc's oxidation number tends to be +2, and this is just a rule that I memorized when I learned this topic. Please let me know if you still need help and I hope you understood!

As a pure element, the oxidation number of zinc is zero, but in compounds such as  [tex]ZnCO_3\\[/tex] its oxidation number is +2.

Oxidation number also called oxidation state, is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom.

As a pure element, any element or simple compound has an oxidation number of 0. This makes it a lot easier and can be applied for almost any element or compound that uses one atom, like [tex]F_2[/tex], [tex]O_3[/tex], Zn, Fe, etc.

However, in compounds, Zinc's oxidation number tends to be +2.

Learn more about the oxidation number here:

https://brainly.com/question/10079361

#SPJ2

Answer:

is the water that passes through the carbon cycle of atmosphere

Answer:

D. 450 J/kgK

Explanation:

Using the formula as follows:

Q = m × c × ∆T

Where:

Q = amount of heat absorbed/released (J)

m = mass of substance (g)

c = specific heat capacity

∆T = change in temperature (°C)

According to the information provided in this question:

Q = 267.3 kJ = 267300J

m = 18kg

∆T = 318K - 285K = 33K

c = ?

Q = m × c × ∆T

c = Q ÷ m∆T

c = 267300 ÷ 18 × 33

c = 267300 ÷ 594

c = 450 J/kgK

Answer:

Weight = mass × gravitational

Weight = 60 kg × 9.8 ms²

= 588 N

Explanation:

hope it helps

Weight of the boy = Mass of the boy × g

= 60 × 9.8

= 588kgm/s²

= 588N

Answer:

Uses of iron

It is used to manufacture steel and also used in civil engineering like reinforced concrete, girders etc. Iron is used to make alloy steels like carbon steels with additives such as nickel, chromium, vanadium, tungsten, and manganese.

Answer:

iron is used to make water pipes.

used for making machines in industries.

used for making steam engine.

The question is incomplete, the complete question is;

As Danny was pouring cereal for his breakfast, he noticed that the cereal box says that the cereal contains 5 milligrams of iron per serving. Danny decided to perform an experiment to test this claim. He found that the cereal contains 4.6 milligrams of iron per serving. Based on Danny's measurement, the value reported on the label is ( CORRECT OR INCCORECT) because A: (IT IS DIFFERENT FROM THE VALUE DANNY MEASURED) B: (IT IS REORTED TO THE NEAREST MILLIGRAM) C: (IT USES THE SAME UNITS THAT DANNY USED).

Answer:

CORRECT because IT IS REORTED TO THE NEAREST MILLIGRAM

Explanation:

In mathematics, values may be rounded up or down as required. In the case of this measurement of cereals by Danny, it is customary to measure the amount of iron per serving to the nearest milligram.

As such, even though Danny found out that the actual amount of iron per serving in the cereal is 4.6 milligrams, the value reported on the cereal box is still correct because it was reported to the nearest milligram hence the value had to be rounded up.

Answer: The answer is D:

Answer:

The answer is Option D