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just olya [345]
3 years ago
6

Which of the following is a compound? a. iron b. lead c. helium d. methane

Chemistry
1 answer:
Lana71 [14]3 years ago
6 0
The correct answer is d) methane (CH_4)

The other options are elements.
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How many grams of As2S3 are in 3.25 moles?
laiz [17]

Answer:

Explanation:

Molar mass of As2S3= {75(2) + 32(3)}

= 150 + 96 = 246g/mol

Amount = 3.25mole

And

Amount = mass/ molar mass

mass = amount × molar mass

Mass = 3.25 × 246

mass = 799.5g

6 0
4 years ago
There are two isotopes of an unknown element, X-19 and X-21. The abundance of X-19 is 14.55%. A weighted average uses the percen
alekssr [168]

Answer:

2.765amu is the contribution of the X-19 isotope to the weighted average

Explanation:

The average molar mass is defined as the sum of the molar mass of each isotope times its abundance. For the unknown element X that has 2 isotopes the weighted average is defined as:

X = Mass X-19 * Abundance X-19 + MassX-21 * Abundance X-21

The contribution of the X-19 isotope is its mass (19.00 amu) times its abundance (14.55% = 0.1455). That is:

19.00amu * 0.1455 =

2.765amu is the contribution of the X-19 isotope to the weighted average

8 0
3 years ago
Which activity might help to increase the validity of this experiment?
MArishka [77]
A should be the answer because the more you test an experiment the more data you have to rely on changing the experiment would cause you to have different outcomes making the results different and unreliable so B, C, and D is not going to be the answer Hope this helps
5 0
3 years ago
What’s the difference between internal stimuli and external stimuli
oee [108]

Answer:

An external stimuli is a stimulus that comes from outside an organism and causes a reaction.An internal stimuli is a stimulus that comes from inside an organism.

3 0
3 years ago
How many grams is 4.2X10^24 atoms of sulfur?
ipn [44]
First find the number of moles of sulfur using dimensional analysis with avogadro’s number as the conversion factor. 4.2*10^24 atoms * (1 mol/6.022*10^23 atoms) = 7.0 mol sulfur. The molar mass of sulfur is 32.06 g/mol, which is found on the periodic table as sulfur’s (S) atomic weight. Use dimensional analysis again with the molar mass of sulfur as the conversion factor. 7.0 mol * 32.06 g/mol = 224.42 g sulfur. Since the problems gives us two significant figures, round the mass of sulfur to 220 grams, or 2.2 * 10^2 g.
7 0
3 years ago
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