Answer:
They attract each other
Explanation:
A magnet has two poles;
North pole and south pole
When two opposite poles are placed close to each other, they attract each other. The short rule is opposite opes attract.
When two like poles are placed close to each other, they repel each other. The short rule is like poles repel.
<span>a. increase in temperature
</span><span>d. phase change
Hope this helps!</span>
the mass of potassium iodide is 0.360 g
calculation
step 1: write the balanced molecular equation
Pb(NO3)2 (aq) + 2 Ki (s)→ Pbi2(s) + 2KNO3
step 2 ; calculate the moles of Pbi2
moles = mass /molar mass
= 0.500 g / 461 .0 g/mol =0.0011 moles
step 3: use the mole ratio to calculate the moles of Ki
Ki: Pbi2 is 2:1 therefore the moles of ki = 0.0011 x 2/1 = 0.0022 moles
step 4 : find the mass of Ki
mass= moles x molar mass
=0.0022 moles x 166g/mol =0.365 g which is approximate 0.360 g
Answer: The specific heat capacity of metal is
Explanation:
As we know that,
where,
= mass of metal = 35 g
= mass of water = 220 g
= final temperature =
= temperature of metal =
= temperature of water =
= specific heat of metal = ?
= specific heat of water =
Now put all the given values in equation (1), we get
Therefore, the specific heat capacity of metal is
Answer:
- <u>1. Use small pebbles</u>
- <u>2. Stir the solution</u>
Explanation:
He should use the material with the largest surface area to speed up the dissolution of the sodium hydroxide.
From the verbal description you migth infere that the small pebbles are small enough to permit a larger contact area than the large flakes.
In the first figure, I attach a picture of two samples of sodium hydroxide, to compare<em> small pebbles </em>and <em>large flakes</em>, showing precisely that the small granules should have a larger contact area than the larger flakes.
Thus, <em>Br. Belland</em> should use the <em>small pebbles</em> form <em>to create </em>his <em>solution </em>to have the<em> greatest speed.</em>
<em>To speed up the dissolution</em>, the other recomendation is to stir the solution. The factors that most affect the speed of dissolution are:
- The contact area
- Stirring
- Temperature.
The graph attached is the solubility curve for sodium hydroxide. It shows that it is more soluble at high temperatures, thus by raising the temperature you can dissolve more sodium hydroxide, but, since the dissolution of sodium hydroxide is largely exothermic, the temperature will raise any way and heating the solution could incrase the temperature more than desired, creating some risks. That is why I do not recommend to heat up the sodium hydroxide, but to stir the solution to speed up the dissolution.