4. Will the net force be balanced or unbalanced?<br> 7N<br> 4N<br> A. Balanced<br> B. Unbalanced

Determine the percentage of carbon and hydrogen in ethane C2H6 if the molecular weight is 30.

Naddika [18.5K]

Answer:

Percentage of carbon:

${ \tt{ = \frac{24}{30} \times 100\%}} \\ = 80\%$

Percentage of hydrogen:

${ \tt{ = \frac{6}{30} \times 100\%} } \\ = 20\%$

8 0

3 years ago

What is the concentration of bromide, in ppm, if 12.41 g MgBr2 is dissolved in 2.55 L water.

pav-90 [236]

Answer:

concentration of bromide (Br⁻) = 4234 mg/L = 4234 ppm

Explanation:

ppm (parts per million) concentration is defined as the mass (in milligrams) of a substance dissolved in one liter of solution.

In our case we have:

mass of MgBr₂ = 12.41 g

volume of water (which is equal to the final solution volume) = 2.55 L

Now we devise the following reasoning:

if 12.41 g of MgBr₂ are dissolved in 2.55 L of water

then X g of MgBr₂ are dissolved in 1 L of water

X = (1 × 12.41) / 2.55 = 4.867 g of MgBr₂

if in 184 g (1 mole) of MgBr₂ we have 160 g of Br⁻

then in 4.867 g of MgBr₂ we have Y g of Br⁻

Y = (4.867 × 160) / 184 = 4.232 g of bromide (Br⁻)

4.232 g of bromide (Br⁻) = 4234 mg of bromide (Br⁻)

concentration of bromide (Br⁻) = 4234 mg/L = 4234 ppm

7 0

3 years ago

What is 694,563,239 rounded to the nearest thousand

lina2011 [118]

694,563,239 rounded to the nearest thousand is 694,563.

It's because the first digit from the right is for ones, second for tens, third for hundreds and fourth for thousands and that's the one that we should take a closer look at. You can round it either to 3 or 4, depends on the digit of hundreds. In this case 3239 is clearly closer to 3000 than 4000, that's why we round it to 694,563, not 694,564.

6 0

3 years ago

Read 2 more answers

Convert the composition of the following alloy from atom percent to weight percent (a) 44.9 at% of silver, (b) 46.3 at% of gold,

vesna_86 [32]

Answer:

Mass percentage of gold : 33.35%

Mass percentage of silver: 62.80%

Mass percentage of copper : 3.85%

Explanation:

$N=n\times N_A$