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2 years ago

Question

Chemistry

1 answer:

Nonamiya [84]2 years ago

5 0

Answer:

1.7 mL

Explanation:

start with formula M1V1=M2V2

then plug in values (3)V1=(100)(.05) and solve for V1

V1= 1.66

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Which of the following trends can be identified on the periodic table?

Jet001 [13]

Answer:

D) atomic radii increase from top to bottom of a group

Explanation:

Atomic radii trend along group:

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.

As the size of atom increases the ionization energy from top to bottom also decreases because it becomes easier to remove the electron because of less nuclear attraction and as more electrons are added the outer electrons becomes more shielded and away from nucleus.

Other options are incorrect because,

A) atomic radii increase from left to right across the period

Correct = atomic radii decreases from left to right across the period

B) ionization energy increases from top to bottom within a family

Correct = ionization energy decreases from top to bottom within a family

C) electronegativity decreases from left to right across a period

Correct = electronegativity increases from left to right across a period

8 0

3 years ago

If we start with 1.000 g of strontium-90, 0.805 g will remain after 9.00 yr. This means that the of strontium-90 is ________ yr.

lesantik [10]

The question is incomplete, here is the complete question.

If we start with 1.000 g of strontium-90, 0.805 g will remain after 9.00 yr. This means that the half-life of strontium-90 is ________ yr.

a. 28.8 b. 30.9 c. 35.4 d. 32.2

Answer : The half-life of strontium-90 is 28.8 years.

Explanation :

This is a type of radioactive decay and all radioactive decays follow first order kinetics.

First we have to calculate the rate constant.

Expression for rate law for first order kinetics is given by :

$k=\frac{2.303}{t}\log\frac{a}{a-x}$

where,

k = rate constant

t = time taken for decay process = 9.00 year

a = initial amount or moles of the reactant = 1.000 g

a - x = amount or moles left after decay process = 0.805 g

Putting values in above equation, we get:

$k=\frac{2.303}{9.00}\log\frac{1.00}{0.805}$

$k=0.0241\text{ year}^{-1}$

To calculate the half-life, we use the formula :

$k=\frac{0.693}{t_{1/2}}$

$0.0241\text{ year}^{-1}=\frac{0.693}{t_{1/2}}$

$t_{1/2}=28.8\text{ years}$

Therefore, the half-life of strontium-90 is 28.8 years.

5 0

2 years ago

What is the total mass of oxygen contained in 8.20g of benzoic acid (C6H5COOH)

VashaNatasha [74]

Answer:

Mass of oxygen = 2.2 g

Explanation:

Given data:

Mass of benzoic acid= 8.20 g

Mass of oxygen= ?

Solution:

Molar mass of oxygen = 16×2 g/mol

Molar mass of C₆H₅COOH = 7×12 + 1×6 + 2×16

Molar mass of C₆H₅COOH = 84 + 6 + 32

Molar mass of C₆H₅COOH = 122g/mol

Mass of oxygen in 8.20 g of C₆H₅COOH :

Mass of oxygen = 32 g.mol⁻¹/122 g.mol⁻¹ × 8.20 g

Mass of oxygen = 2.2g

4 0

2 years ago

Which statements are true of solutions?

Dimas [21]

Answer: they contain solutes and solvents, their particles must be evenly distributed, they may contain solid liquid and gas simultaneously, and they are homogeneous matter.

Explanation:

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2 years ago

Which disease is caused when white blood cells are produced in excess?

marin [14]

Answer:

it can cause blood cancer (leukemia)

4 0

3 years ago