Can someone help me with this

What part of the sun do we see from earth?

NISA [10]

Answer:

photosphere

Explanation:

photosphere

There are 3 main layers of the Sun that we can see. They are the photosphere, the chromosphere and the corona. Together they make up the "atmosphere" of the Sun. The part of the Sun that glows (and that we see with the naked eye) is called the photosphere

8 0

3 years ago

Read 2 more answers

A method used by the U.S. Environmental Protection Agency (EPA) for determining the concentration of ozone in air is to pass the

baherus [9]

Answer: 1. $9.08\times 10^{-6}$ moles

2. 90 mg

Explanation:

$O_3(g)+2NaI(aq)+H_2O(l) \rightarrow O_2(g)+I_2(s)+2NaOH(aq)$

According to stoichiometry:

1 mole of ozone is removed by 2 moles of sodium iodide.

Thus $4.54 \times 10^{-6}$ moles of ozone is removed by = $\frac{2}{1}\times 4.54 \times 10^{-6}=9.08\times 10^{-6}$ moles of sodium iodide.

Thus $9.08\times 10^{-6}$ moles of sodium iodide are needed to remove $4.54\times 10^{-6}$ moles of $O_3$

2. $\text{Number of moles of ozone}=\frac{0.01331g}{48g/mol}=0.0003moles$

According to stoichiometry:

1 mole of ozone is removed by 2 moles of sodium iodide.

Thus 0.0003 moles of ozone is removed by = $\frac{2}{1}\times 0.0003=0.0006$ moles of sodium iodide.

Mass of sodium iodide= $moles\times {\text {molar mass}}=0.0006\times 150g/mol=0.09g=90mg$ (1g=1000mg)

Thus 90 mg of sodium iodide are needed to remove 13.31 mg of $O_3$ .

3 0

2 years ago

The liter is used to measure _____. weight mass volume length

Ket [755]

the answer to your question is

volume

4 0

3 years ago

Read 2 more answers

Chalcopyrite is an ore with the composition cufes2. what is the percentage of iron in a 39.6 g sample of this ore? answer in uni

iren2701 [21]

Well it depends on percentage by what, but I'll just assume that it's percentage by mass. For this, we look at the atomic masses of the elements present in the compound. Cu has an atomic mass of 63.546 amu Fe has 55.845 amu and S has 36.065 amu Since there are 2 molecules of Sulfur for each one of Cu and Fe, we'll multiply the Sulfur atomic weight by 2 to obtain 72.13 amu So we have not established the mass of the compound in amus 63.546 + 55.845 + 72.13 = 191.521 That is the atomic mass of Chalcopyrite. and Iron's atomic mass is 55.845 So to get the percentage, or fraction of iron, we take 55.845 / 191.521 Which comes out to 29.15% by mass Mass of the sample is not needed for this calculation, but since the question mentions it I would go ahead and check if the question isn't also asking for the mass of Iron in the sample as well, in which case you just find the 29.15% of 67.7g

5 0

3 years ago

_Li + __F2 → _LIF How do I balance this?

Semmy [17]

Answer:

2Li + F₂ → 2LiF

Explanation:

The reaction expression is given as:

Li + F₂ → LiF

We are to balance the expression. In that case, the number of atoms on both sides of the expression must be the same.

Let use a mathematical approach to solve this problem;

Assign variables a,b and c as the coefficients that will balance the expression:

aLi + bF₂ → cLiF

Conserving Li: a = c

F: 2b = c

let a = 1, c = 1 and b = $\frac{1}{2}$

Multiply through by 2;

a = 2, b = 1 and c = 2

2Li + F₂ → 2LiF

5 0

2 years ago