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3 years ago

Which of the following statements is true?

Chemistry

1 answer:

sattari [20]3 years ago

6 0

<h2>Answer:</h2>

The last statement is true. which is:

Mg is less reactive than Na because Mg has to lose one more electron than Na to complete its outermost shell.

<h3>Explanation:</h3>

Mg belongs to group II and Na belongs to group I.

Group II elements are less reactive than Group I elements. This is because it is more difficult to lose two electrons compared to losing just one electron.

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NEED HELP ASAP ITS DUE TODAY THESE QUESTIONS

beks73 [17]

Density can be defined as the mass of the substance in unit volume.

Density = mass / volume

Hence, g/mL and kg/L can be used as the units of density.

Those units are interchangeable because when converting one unit into other one nothing will happen to the value.

That is because when converting the g into kg, you have to multiply the value by 1 x 10⁻³. When converting mL into L, you should again multiply the volume by 1 x 10⁻³. Then those 1 x 10⁻³ will cancel off and the original value will remain as same.

Answer is 2.70 g/mL.

<em>Explanation;</em>

Mass of the block = 146 g

Volume of the block = length x width x height

= 6.0 cm x 3.0 cm x 3.0 cm

= 54 cm³ = 54 mL

Density = mass / volume

= 146 g / 54 mL

= 2.70 g/mL

Answer is 3.39 g/mL.

<em>Explanation;</em>

When immersing an object in a solution, the increased volume indicates the volume of that object.

Hence,

Volume of the object = increased volume of water level

= final volume - initial volume

= 27.8 mL - 21.2 mL

= 6.6 mL

Mass of the object = 22.4 g

Density = Mass / Volume

= 22.4 g / 6.6 mL

= 3.39 g/mL

Accepted value is the value that scientists and community accept as true. This is a theoretical value.

But the measured value is the value that you obtain from doing experiments. This is the actual value.

If your measured value is more close to the accepted value, then your measured value is more precise. But, if your measured value is far away from accepted value means that your value is not precise and there may have some errors.

Answers : Percent error is 9.11 %

The element which has 7.13 g/cm³ as density is Zinc (Zn).

<em>Explanation;</em>

Percent error can be calculated by using following formula.

% error = ( (measured value - accepted value) / accepted value ) x 100%

= ( (7.78 g/cm³ - 7.13 g/cm³) / 7.13 g/cm³ ) x 100%

= 9.11 %

6 0

3 years ago

A solution prepared by mixing 10 ml of 1 m hcl and 10 ml of 1.2 m naoh has a ph of

blagie [28]

Answer: pH of resulting solution will be 13

Explanation:

pH is the measure of acidity or alkalinity of a solution.

Moles of $H^+$ ion = $Molarity\times {\text {Volume in L}}=1M\times 0.01L=0.01mol$

Moles of $OH^-$ ion = $Molarity\times {\text {Volume in L}}=1.2M\times 0.01L=0.012mol$

$HCl+NaOH\rightarrow NaCl+H_2O$

For neutralization:

1 mole of $H^+$ ion will react with 1 mole of $OH^-$ ion

0.01 mol of $H^+$ ion will react with = $\frac{1}{1}\times 0.01mole$ of $OH^-$ ion

Thus (0.012-0.01)= 0.002 moles of $OH^-$ are left in 20 ml or 0.02 L of solution.

$[OH^-]=\frac{0.002}{0.02L}=0.1M$

$pOH=-log[OH^-]$

$pOH=-log[0.1]=1$

$pH+pOH=14$

$pH=14-1=13$

Thus the pH of resulting solution will be 13

7 0

3 years ago

Enter the formula for the compound cobalt(II) phosphate. Express your answer as a chemical formula.

alexira [117]

Answer:

$Co_3(PO_4)_2$

Explanation:

Naming of the ionic compounds:-

The name of the cation is written first and the the name of the anion is written after the name of the cation separated by single space.
The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.
In case of transition metals, the oxidation state are written in roman numerals in bracket in front of positive ions.

Hence, given ionic compound:-

Cobalt(II) phosphate

So, Cobalt will have a positive charge of +2

Phosphate is $PO_4^{3-}$

So, the formula is :-

Co $PO_4^{3-}$

2 3

$Co_3(PO_4)_2$

5 0

3 years ago

A hydrogen bond can occur between:

Readme [11.4K]

A hydrogen bond occurs between a hydrogen from one molecule and an oxygen from another molecule. Option D

<h3>What is the hydrogen bond?</h3>

The hydrogen bond is one that is responsible for association in molecules. It occurs when hydrogen is covalently bonded to a highly electronegative element such as oxygen, nitrogen or Sulphur.

Thus, a hydrogen bond occurs between a hydrogen from one molecule and an oxygen from another molecule. Option D

Learn more about hydrogen bonding:brainly.com/question/10904296?

#SPJ1

5 0

2 years ago

Negative charge is placed in an eletric

leonid [27]

I would i have think it is either a) east or c) west b/c couldn’t go by it self

7 0

3 years ago