Pls help!!!
You are given a type of element by a teacher and she asks you to identify it.What should you do?Explain your answer​

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:

1;1, 2;1, 3;1, 1;2, 1;1, 3;2, 1;3, 2;3, 1;1.

I hope this will help.

Answer:

This is what the answer looks like

Explanation:

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 .

Explanation:

Chemistry Teacher.

Chemical Engineer.

Forensic Scientist.

Geochemist.

Biochemists

Pharmacologist

Analytical Chemist

Envionmental chemist

Water Chemist

Catalysis

Answer:

"Endothermic reaction: In an endothermic reaction, the products are higher in energy than the reactants. Therefore, the change in enthalpy is positive, and heat is absorbed from the surroundings of the reaction."

Explanation:

When enthalpy is positive and delta H is greater than zero, this means that a system absorbed heat. This is called an endothermic reaction. When enthalpy is negative and delta H is less than zero, this means that a system released heat. This is called an exothermic reaction.

The sign of q for an endothermic process is positive because the system is gaining heat. A chemical reaction or physical change is exothermic if heat is released by the system into the surroundings. Because the surroundings are gaining heat from the system, the temperature of the surroundings increases.

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Sodium salt might not be prepared by double decomposition because the method is used in preparing insoluble salts.

Double decomposition method serves as the method that is used in preparing compounds which entails reaction between two soluble compounds and after reaction soluble and insoluble products are produced.

Therefore, since most of the sodium salt are soluble salt , Double decomposition cannot be used to prepare them.

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Answer:

C 760 mm of hg

because this is the atmospheric pressure at sea level

The empirical formula is the simplest formula of a chemical compound.

To find the empirical formula, we take the following steps;

1) O - 88.10/16,      H - 11.190/1

  O - 5.5,               H - 11.19

  O - 5.5/5.5,        H - 11.19/5.5

  O -  1,                 H - 2

Empirical formula = OH2

2) C - 41.368/12  H - 8.101/1,   N - 32.162/14,   O - 18.369/16

   C - 3,               H - 8,           N - 2,                  O - 1

   C - 3/1,            H - 8/1          N - 2/1                 O - 1/1

    C - 3,             H - 8,           N - 2,                   O - 1

Empirical formula = C3H8N2O

To obtain the molecular formula where n = number of atoms of each element;

Molecular weight = 174.204 g/mol

[ 3(12) + 8(1) + 2(14) + 16]n = 174

n= 174/88

n = 2 (to the nearest whole number)

Hence, we have;

[C3H8N2O]2

The molecular formula is C6H16N4O2

3)  C - 19.999/12,  H - 6.713/1,   N - 46.646/14,   O - 26.641/16

    C - 2,                H - 7,            N -  3,                 O - 2

    C - 2/2,            H - 7/2,         N -   3/2,             O - 2/2

    C - 1,                H - 4,            N -  2,                  O - 1

Empirical formula - CH4N2O

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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:

B. The carbons on either side of the double bond are Pointed in opposite directions

Answer:

1 Ca(NO3)2

Calcium- Ca, Valency 2

Nitrate- NO3, Valency 1

AFTER CRISS CROSS:

Ca1(NO3)2

Ca(NO3)2

2 sodium bicarbonate = NaHCO3

Na = Sodium = (Na)+

HCO3 = bicarbonate = (HCO3) -

Na HCO3

3 magnesium   nitrite

   +2                 _ 1

Mg2(NO3)2

4 Na    Cl

    +1    _1

formula NaCl

5 hydrogen         sulphide  

H                       SO4

+1                       _2

formula H2SO4

6  H    Cl

  +1     _1

HCl

7 AL2     HSO4

  +2        -2

AL2(HSO4)3

8  NH4   Cl

   +1      _1

NH4Cl

9 NH4     SO4

  +1           _2

(NH3)2SO4

10  H   NO3

    +1    _1

HNO3

Answer:

B. Protons and Neutrons

Answer:

Option"B" is correct.

MARK ME BRAINLISTS

Answer:Water contains Oxygen the purified the methane gas

Explanation:

Answer:

7.2

Explanation:

you first have to find the number of moles of nitrogen dioxide by using the number of moles for calcium nitrate and the mole to mole ratios

number of moles of calcium nitrate=mass/mm

=16.4/102

=0.16g/mol

then you use the mole to mole ratios

2 : 4

0.16: x

2x/2=0.64/2

x=0.32g/moles of nitrogen dioxide

then you use the formula for the volume

v=22.4n

=22.4×0.32

=7.2

I hope this helps

Answer:

if wrong sorry ok????

Answer:

A and D are the answers

Explanation:

the other two don't make sense

The statements C and D are correct, i.e., curly hair have different protein structure from straight hair and curly hair results from a change in the gene.

Proteins are biomolecules made of amino acids. Proteins are very essential to all living things and contributes the body structure. Proteins are mainly up taken through diet and they are the main source of energy.

Hair is made of keratin protein. Keratin makes up our skin and nails too.Curly hair is originating by birth not developing over time. Curly hair is more likely to be occurring through inheritance.

The protein structure the hair follicle is some more bend for curly hair. Curly hair and straight hair originates from different gene traits. The gene type is inherited from the parents.

Hence, for people with curly hair have different protein structure and it result from a change in gene that code for hair structure. Thus options C and D are correct.

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Explanation:

here's the answer to your question

Answer:

Potentials of any other electrodes are compared with that of the standard hydrogen electrode at the same temperature. Hydrogen electrode is based on the redox half cell: 2 H+(aq) + 2 e− → H2(g)..

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:

D.Something that can be observed or measured without changing the identity of the substance.

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: A reaction element are those elements that can take part in a chemical reaction.

Explanation:

An element is made up of atoms that has the same atomic number. It is the basic material of which all matter is composed of. These elements cannot be broken down further into smaller substances by any chemical reaction. Each element has a unique number of protons in its atom. For example,

--> a hydrogen atom has 1 proton,

--> a Helium atom has 2 protons,

--> a Lithium atom has 3 protons, and

--> a carbon atom has 6 protons.

A chemical reaction on the other hand involves rearrangement of the constituent atoms of reactants to create different substances as products. The bonds between atoms are either broken or created to form new molecules. There are different types of chemical reaction which includes:

--> Decomposition reaction

--> Neutralization reaction

--> single displacement reaction and

--> combustion reaction.

Answer:

A linear molecule has a bond angle of 180°

Answer:

[tex]\boxed {\boxed {\sf B. \ 0.5 \ M}}[/tex]

Explanation:

Molarity is a measure of concentration in moles per liter. The formula for calculating molarity is:

[tex]molarity= \frac{moles \ of \ solute}{ liters \ of \ solution}[/tex]

There are 2 moles of a compound or the solute. There are 4 liters of water or the solution.

Substitute the values into the formula.

[tex]molarity = \frac{ 2 \ mol}{ 4 \ L}[/tex]

Divide.

[tex]molarity= 0.5 \ mol /L[/tex]

1 mole per liter is equal to 1 Molar, so the solution's molarity of 0.5 mol/L is equal to 0.5 M.

[tex]molarity = 0.5 \ M[/tex]

The molarity of the solution is 0.5 Molar and choice B is correct.

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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