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3 years ago

Give the number of significant figures in this number: 40

2 answers:

8 0

The # 4 is the only significant # in 400.. Trailing 0's r not significant unless there is a decimal.

in 0.7000, there are 4 significant #'s.

Kipish [7]3 years ago

3 0

The amount of significant figures is 1

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What is the mass of one gram of calcium?

Anvisha [2.4K]

pls follow me

Explanation:

The mass of one atom of calcium is the same as the molar mass of the calcium. Also, the atomic mass of calcium is 40.078 g/mol.

8 0

3 years ago

An aqueous solution containing 10 g of an optically pure compound was diluted to 500 mL with water and was found to have a speci

lapo4ka [179]

Answer:

Optical purity = 76.9231 %

Specific rotation of mixture = - 97.6923 °

Explanation:

The mass of the racemic mixture = 3 g

It means it contains R enantiomer = 1.5 g

S enantiomer = 1.5 g

Amount of Pure R = 10 g

Total R = 11.5 g

Total volume = 500 mL + 500 mL = 1000 mL = 1 L

[R] = 11.5 g/L

[S] = 1.5 g/L

Enantiomeric excess = $\frac {Excess}{Total\ Concentration}\times 100$ = $\frac {11.5-1.5}{11.5+1.5}\times 100$ = 76.9231 %

Optical purity = 76.9231 %

Also,

Optical purity = $\frac {optical\ rotation\ of\ mixture}{optical\ rotation\ of\ pure\ enantiomer}\times 100$

Optical rotation of pure enantiomer = −127 °

$76.9231=\frac {optical\ rotation\ of\ mixture}{-127^0}\times 100$

Specific rotation of mixture = - 97.6923 °

6 0

3 years ago

Which of the following substances contains exactly 6.02 x 1023 formula units of the given

aniked [119]

Answer:

your question is incomplete and its

$6.02 \times {10}^{23?}$

particles which is one mole of a substance

Explanation:

you can solve the question by using this formular 1 mole of a substance=mass of the substance/ its molar mass

you find molar mass of a compound by adding individual molar masses of elements in that compound

3 0

2 years ago

From top to bottom in most groups of elements atomic radii tend to

kogti [31]

As you go down a group on the periodic table, atomic radii tend to increase because elements with larger atomic numbers have more occupied electron levels which take up more space surrounding the nucleus.

I hope this helps.

3 0

4 years ago

A gas at 400 k is placed in a 4.0 l moveable piston. The gas is cooled to 252 k. What is the new volume of the piston?

katrin [286]

Answer:

2.52L

Explanation:

Given parameters:

T₁ = 400K

V₁ = 4L

T₂ = 252K

unknown

V₂ = ?

Solution:

To solve this problem, we are going to apply charle's law. The law states that the volume of a fixed mass of gas is directly proportional to temperature provided pressure is constant.

Mathematically,

$\frac{V_{1} }{T_{1} } = \frac{V_{2} }{T_{2} }$

Substitute and solve for V₂

$\frac{4}{400} = \frac{V_{2} }{252}$

V₂ = 2.52L

6 0

3 years ago