Answer:
Explanation:
the answer is C, sometimes it can be brown
Answer:

Explanation:
A number in scientific notation has the form N × 10ⁿ
where N is a decimal number called the mantissa and n is an integer called the exponent.
We must have 1 ≤ N < 10
Step 1. Determine the mantissa
Move the decimal place to the left to create a new number between 1 and 10.
145 000 000 ⟶ 1.450 000 00; N = 1.45
Step 2. Determine the exponent.
The exponent is the number of times you moved the decimal to get the mantissa.
You moved the decimal eight places to the left, so the exponent n = 8.
Step 3. Write the number in scientific notation
The number in scientific notation is
.
Answer:
0.12 M hydrofluoric acid + 0.17 M potassium fluoride
Explanation:
To make a buffer, you must to have an aqueous mixture of a weak acid and its conjugate base or vice versa.
Knowing that:
0.32 M calcium chloride + 0.27 M sodium chloride: <em>is not a good buffer system </em>because CaCl₂ and NaCl are both salts.
0.35 M ammonia + 0.36 M calcium hydroxide <em>is not a good buffer system </em>because ammonia is a weak base but calcium hydroxide is a strong base
0.19 M barium hydroxide + 0.28 M barium chloride <em>is not a good buffer system </em>because Ba(OH)₂ is a strong base.
0.12 M hydrofluoric acid + 0.17 M potassium fluoride <em>is a good buffer system </em>because HF is a weak acid and KF (F⁻ in aqueous medium), is its conjugate base
0.20 M hydrobromic acid + 0.22 M sodium bromide <em>is not a good buffer system </em>because HBr is a strong acid.
Answer:

Explanation:
Let's call the unknown compound X.
1. Calculate the mass of each element in 1.23383 g of X.
(a) Mass of C

(b) Mass of H

(c)Mass of Fe
(i)In 0.4131g of X

(ii) In 1.2383 g of X

(d)Mass of O
Mass of O = 1.2383 - 0.632 07 - 0.074 157 - 0.195 67 = 0.336 40 g
2. Calculate the moles of each element

3. Calculate the molar ratios
Divide all moles by the smallest number of moles.

4. Round the ratios to the nearest integer
C:H:O:Fe = 15:21:1:6
5. Write the empirical formula
