Answer:
Most common insulation materials work by slowing conductive heat flow and--to a lesser extent--convective heat flow. Radiant barriers and reflective insulation systems work by reducing radiant heat gain. To be effective, the reflective surface must face an air space.
Explanation:
To be effective, the reflective surface must face an air space.
Answer:
- 1. Dimensions: The sheet can be cut into several smaller pieces.
- 2. Shape: the sheet can be formed into a paper ball or any other shape (using origami for example).
- 3. Color: You can use crayons to paint the sheet and change its color.
Explanation:
<em>Physical changes</em> do not change the chemical properties. They do not transform the compounds that form the substances. They do not break and or form chemical bonds.
When you change the form, the state (solid, liquid or gas), the color, you are just changing physical properties.
Only chemical changes change the compounds that form the substance. For instance, if you burn the <em>sheet of paper</em>, then you are causing a chemical change because the organic matter in the paper will react with oxygen forming CO₂ and water, but by cutting, folding, smashing, or coloring with crayons, the compounds in the<em> sheet of paper</em> do not change.
<span>An iron fence is left on painted and it reacts with the oxygen in the air form forming rust. the formation of the rest is an oxidation-reduction reaction but it is also an example of a double-displacement reaction.
</span><span>cooking requires continuous addition of energy to the chemical reactions the are taking place the chemical reaction involved in cooking can be described as a chemical change.
</span><span>measuring how quickly a reactanat disappears in one way to measure the rate of the reaction</span>
An electron has a relative mass of 0, whilst an alpha particle has a relative mass of 4
An electron has a relative mass of 0, whilst a proton has a relative mass of 1
A neutron has a relative mass of 1, whilst an alpha particle has a relative mass of 4
A neutron has a relative mass of 1, and a proton also has a relative mass of 1
The mass of NaN3 needed to produce 17.2 L nitrogen at STP is calculated as follows
find the moles of N2 produced at STP
At STP 1mole of gas = 22.4 L , what about 17.2 L of nitrogen
by cross multiplication
= (1 mole x17.2 L)/ 22.4 L= 0.768 moles
2NaN3 =2Na +3 N2
by use of mole ratio between NaN3 to N2 (2:3) the moles of NaN3 = 0.768 x2/3 = 0.512 moles of NaN3
mass of NaN3 is therefore =moles of NaN3 xmolar mass of NaN3
=0.512moles x 65 g/mol =33.28 grams of NaN3
