Answer: A) grinding coffee beans
Explanation:
A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.
A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.
1. Grinding coffee : Only change in size takes place, thus a physical change
2. Baking a cake: the chemical reaction occurs by combination of flour with oxygen , thus a chemical change.
3.:converting water to hydrogen and oxygen: The decomposition iof water takes place, thus is a chemical change
4.Burning of coal: the chemical reaction occurs by combination of carbon with oxygen , thus a chemical change.
Answer:this air polluction here.
Explanation:
air and soil polluction
Heat Transfer Lab
The following represents a lab set up for heat transfer. The cup on the left started with boiling water at 100 degrees C and the cup on the right has water at 20 degrees C. There is an aluminum bar between the two cups allowing heat to transfer from one cup into the other. The set up will be left alone for 20 minutes and temperatures of each cup of water will be recorded every minute for 20 minutes.
mag-aral ka
2.15 x 10⁻³mL
Explanation:
Given parameter:
Volume of blood sample in uL = 2.15uL
Conversion uL → mL
micro- and milli- are both prefixes of sub-units.
liter is a unit of volume of a substance.
micro - is 10⁻⁶
milli- is of the order 10⁻³
The problem is converting from micro to milli:
if we multiply 10⁻⁶ by 10³ we would have our milli;
1000uL = 1mL
2.15uL : 2.15uL x 
= 2.15 x 10⁻³mL
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Answer:
Explanation:
Assuming that all caculations are at normal pressure and -1.72°C :
Where
is the number of moles of hydrogen
is the mass of hydrogen
is the density of hydrogen
