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3 years ago

What gas makes up close to 1/4 of the air surronding the earth?

Chemistry

2 answers:

Olegator [25]3 years ago

4 0

The answer is hydrogen. the first element in the periodic table.

SIZIF [17.4K]3 years ago

3 0

Hydrogen is the answer

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Which of the example most complete description an objects motion?

Rashid [163]

<span>c] The golfer sent the golf ball flying toward the cup to score a hole in one.</span>

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3 years ago

A cleaning bottle contains 83.1 g of ammonia. How many molecules of ammonia are in the bottle?

Tasya [4]

Answer:

2.94 x $10^2^4$

Explanation:

First we need to find out how many moles of ammonia there are, using the formula: Mass = mr x moles.

We know the mass is 83.1g, now we need to find the mR of ammonia - NH3.

N = 14, H = 1, so 14 + (3x1) = an mr of 17.

Moles = mass/ mr = 83.1/17 = 4.8882

Now we can multiply the moles by avogadro's constant to find the number of molecules:

4.8882 x (6.02 x $10^2^3$ ) = 2.94 x $10^2^4$ molecules of ammonia

4 0

3 years ago

Which of the following is the Arrhenius definition of an acid?

castortr0y [4]

Arrhenius is a substance that dissociates in water to produce hydrogen ions (H+) and there is a clear answer which coincides with this definition. The correct answer is definitely b. a substance that increases the concentration of hydronium ions when dissolved in water.

5 0

3 years ago

2. Sitting on a bench top are several samples: lithium metal (d = 0.53 g/mL), gold (d = 19.3 g/mL), aluminum (d = 2.70 g/mL), an

Snezhnost [94]

Answer:

The sample of lithium occupies the largest volume.

Explanation:

Given the densities for the four elements, we have the expression $d=\frac{m}{V}$ that shows the relationship between mass and Volume to express the density of an element.

For each element we have:

$d_{lithium}=\frac{m_{lithium}}{V_{lithium}}=0.53g/mL$

$d_{gold}=\frac{m_{gold}}{V_{gold}}=19.3g/mL$

$d_{aluminum}=\frac{m_{aluminum}}{V_{aluminum}}=2.70g/mL$

$d_{lead}=\frac{m_{lead}}{V_{lead}}=11.3g/mL$

The problem says that all the samples have the same mass, so:

$m_{lithium}=m_{gold}=m_{aluminum}=m_{lead}=m$

it means that m is a constant

Now, solving for the Volume in each element and with m as a constant, we have:

$V_{lithium}=\frac{m}{d_{lithium}}$

$V_{lithium}=\frac{1}{0.53\frac{g}{mL}} *m$

$V_{lithium}=1.88\frac{mL}{g}*m$

$V_{gold}=\frac{m}{d_{gold}}$

$V_{gold}=\frac{1}{19.3\frac{g}{mL}} *m$

$V_{gold}=5.18*10^{-2}\frac{mL}{g}*m$

$V_{aluminum}=\frac{m}{d_{aluminum}}$

$V_{aluminum}=\frac{1}{2.70\frac{g}{mL}} *m$

$V_{aluminum}=3.70*10^{-1}\frac{mL}{g}*m$

$V_{lead}=\frac{m}{d_{lead}}$

$V_{lead}=\frac{1}{11.3\frac{g}{mL}} *m$

$V_{lead}=8.85*10^{-2}\frac{mL}{g}*m$

If we assume m = 1g, we find that:

$V_{lithium}=1.88mL$

$V_{gold}=5.18*10^{-2}mL$

$V_{aluminum}=3.70*10^{-1}mL$

$V_{lead}=8.85*10^{-2}mL$

So we can see that the sample of lithium occupies the largest volume with 1.88mL

Note that m only can take positive values, so if you change the value of m, always will be the lithium which occupies the largest volume.

4 0

2 years ago

What is the bond angle between the hydrogen atoms in an ammonia (NH₃) molecule?

dimulka [17.4K]

There are 4 electron pairs (3 bonding and 1 lone pair) so the angle is 107 degrees. The 4 electron pairs are repelled to give a tetrahedral arrangement but the molecule has a pyrimidal shape due to the lone pair.

3 0

3 years ago