Answer:
10.78 → 4 significant figures, pH = 10.78 → [H⁺] = 1.66ₓ10⁻¹¹ M
6.78 → 3 significant figures, pH = 6.78 → [H⁺] = 1.66ₓ10⁻⁷ M
0.78 → 2 significant figures, pH = 0.78 → [H⁺] = 0.166 M
pH always can be expressed by at least 4 significant figures. The [H⁺], can be expressed by, at least 3 significant figures
Explanation:
Significant figures are the numbers of a measurement that have certainty plus a doubtful number (it is associated with the uncertainty in the measurement). For example, if we measure a paper with a ruler and the ruler measures up to centimeters we can say that the paper is 7.5 cm long, with which we know that the paper is 7 cm + 0.5 cm which we associate with uncertainty. In this case we talk about two significant figures. If the sheet measured 7.57 cm we would already be talking about a more precise measurement and in this case with 3 significant figures.
10.78 → 4 significant figures
6.78 → 3 significant figures
0.78 → 2 significant figures
To determine [H⁺], we apply 10^-pH
10⁻¹⁰°⁷⁸ = 1.66ₓ10⁻¹¹ M
10⁻⁶°⁷⁸ = 1.66ₓ10⁻⁷ M
10⁻⁰°⁷⁸ = 0.166 M
Answer: time on earth is measured by tracking earth's movement in relation to the axis
Explanation:
easy science
If it is assumed that there are only two isotopes then the percent abundance needs to add up to 100%
100-35= 65%
The second isotope will have a 65% abundance.
<span />
Answer:
D. MgO
Explanation:
We need to look at the charge of element. (Look at a periodic table for this)
Mg, which is Magnesium, has a charge of 2+ because it's in the second column, or group, from the left.
O, which is Oxygen, has a charge of 2- because it's in the second column, or group, from the right.
Since Mg is 2+, it's the cation and since O is 2-, it's the anion. We can put these two elements together into an ionic compound.
Mg^(2+) and O^(2-) becomes Mg2O2, where we can cancel the 2s: MgO.
Thus, the answer is D.
Hope this helps!
Answer:
Phosphorus, Sulfur, and Selenium are the only <u>poly</u>atomic elements.
Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, and Iodide are all <u>di</u>atomic elements.