All categories

3 years ago

I need help on this science question

Chemistry

1 answer:

ICE Princess25 [194]3 years ago

5 0

Answer:

Explanation:

The kinetic energy of a body is the energy due to the motion of a body. It is mathematically given as;

Kinetic energy = $\frac{1}{2}$ m v²

m is the mass of the body

v is the velocity

Now, let us find the K.E from the given choices;

Option C will have the greatest kinetic energy;

mass = 0.14kg , v = 40m/s

Kinetic energy = $\frac{1}{2}$ x 0.14 x 40² = 112J

You might be interested in

ASAP PLEASE

dimaraw [331]

The mass of Hydrogen is 2 g/mol
The mass of Helium is 4 g/mol

6 0

3 years ago

When planning a simple experiment, what does it mean to “test one variable”?

SSSSS [86.1K]

Answer:

I believe the answer is "b". "During the experiment, the scientist has only one element, or variable, that is changed to test the hypothesis."

Explanation:

I remember from last year but I'm not totally sure. Good luck!

3 0

2 years ago

How many grams of solute are needed to make 37.5 mL of 0.750 M KI solution? Round to three significant digits.

Marysya12 [62]

4.648 gm of solute is needed to make 37.5 mL of 0.750 M KI solution.

Solution:

We will start with the Molarity

$\text { Molarity }=\text { Mole of solute } \div \text { liter of solution }$

Also we know 1000 ml = 1 L

Therefore 37.5 ml by 1000ml we obtained 0.0375L

Equation for solving mole of solute

$\text { Mole of solute }=\text { Molarity } \times \text { Liters of solution }$

Now, multiply 0.750M by 0.0375

Substitute the known values in the above equation we get

$0.750 \times 0.0375=0.0281$

Also we know that Molar mass of KI is 166 g/mol

So divide the molar mass value to get the no of grams.

$0.028 \times 166=4.648$

So 4.648 gm of Solute is required for make 37.5 mL of 0.750 M KI solution.

8 0

3 years ago

4. Write the chemical equation for the reaction that occurs when baking soda (NaHCO3) is

aev [14]

Answer: HCl+NaHCO₃=NaCl+CO₂+H₂O

Explanation:

3 0

3 years ago

Which of the following isoelectronic series is correctly ranked from largest ionic radius to smallest ionic radius? 1. N 3−, O 2

love history [14]

Answer:

Option 1: N⁻³ > O⁻² > F⁻ > Na⁺ > Mg⁺²

Explanation:

Ionic radius is the radius of an atom´s ion in ionic crystal structure. In an ion that lose an electron, to form a cation, the radius of the ion gets smaller, because the repulsion between electrons decrease because fewer electrons are present. Conversely, adding on electron to a neutral atom, to form an anion, causes electron - electron repulsions to increase, so the size of the radius of the ion gets bigger.

Isoelectronic species are ions or elements that have the same number of electrons in their electronic shells but have different overall charges, because of their different atomic numbers.

In a isolelectronic series (same number of electrons), the increase of the positive charge (given by the number of protons in the nucleus), will cause a decrease in radius beacuse the greater electrostatic attraction between the electrons and the nucleus. Consequently, the ion with the greatest nuclear charge will have the smallest ionic radius and the ion with the smallest nulear charge will have the largest ionic radius.

We will use this principle to solve our problem.

In our case, the given ions are:

N⁻³ : Z = 7, e⁻ = 10
O⁻²: Z= 8, e⁻ =10
F⁻: Z = 9, e⁻ = 10
Na⁺: Z= 11, e⁻ = 10
Mg⁺²: Z=12, e⁻ =10

where Z= number of protons, and e⁻ = number of electrons.

Hence the decreasing order of ionic radius is:

N⁻³ > O⁻² > F⁻ > Na⁺ > Mg⁺²

Have a nice day!

4 0

2 years ago