Answer:
addition of aqueous hydrochloric acid
Explanation:
The solubility of copper (ll) hydroxide in water is negligible. This implies that the substance is only slightly soluble in water.
However, the addition of aqueous hydrochloric acid leads to the following reaction;
Cu(OH)2 + 2HCl ---------> CuCl2 + 2H2O
Copper II chloride is soluble in water hence the crystals dissolve when stirred. and the molar solubility increases.
In the periodic table, elements of the same group are characterized by having the same similar properties.
So, first we will check the elements that lie within the same group as <span>beryllium and then we will attempt to choose the elements with atomic mass higher than 130.
So, elements in the same group as </span>beryllium are: magnesium, calcium, strontium, barium and radium.
Among these elements, we will find that:
radium has atomic mass of 226 amu
barium has atomic mass of 137.327 amu
Based on this, the two elements would be barium and radium.
Answer: burning paper
Explanation:
The paper burns in air to form smoke and ash. which makes it a chemical change.
<span>n a metallic bond, atoms of the metal are surrounded by a constantly moving "sea of electrons." This moving sea of electrons enables the metal to conduct electricity.
Answer: Metallic</span>
The answer is 1/16.
Half-life is the time required for the amount of a sample to half its value.
To calculate this, we will use the following formulas:
1.

,
where:
<span>n - a number of half-lives
</span>x - a remained fraction of a sample
2.

where:
<span>

- half-life
</span>t - <span>total time elapsed
</span><span>n - a number of half-lives
</span>
So, we know:
t = 10 min
<span>

= 2.5 min
We need:
n = ?
x = ?
</span>
We could first use the second equation to calculate n:
<span>If:

,
</span>Then:

⇒

⇒

<span>
</span>
Now we can use the first equation to calculate the remained fraction of the sample.
<span>

</span>⇒

<span>⇒

</span>