Answer:  atoms of hydrogen are there in
 atoms of hydrogen are there in 
35.0 grams of hydrogen gas.
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number  of particles.
 of particles.
To calculate the moles, we use the equation:
 
1 mole of hydrogen  =
 =  atoms
 atoms
17.5 mole of hydrogen  =
 =  atoms
 atoms
There are  atoms of hydrogen are there in
 atoms of hydrogen are there in 
35.0 grams of hydrogen gas.
 
        
             
        
        
        
First you need to know the different between an ionic and covalent bond. An ionic bond is the pairing of a metal and non-metal element. A covalent bond is the pairing of 2 nonmetals.
Metals are the elements at the left of the periodic table while non-metals are the elements at the right of the periodic table.
You should also know the diatomic (di means 2) molecules also known as the fab 7. These molecules will always form covalent bonds. These molecules are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. With the subscripts, these molecules would be written as H ₂, N ₂, O ₂, F ₂, Cl ₂, Br ₂, and I ₂.
        
             
        
        
        
a) To find  the mass after t years:we will use this formula:
A = Ao / 2^n when A =the amount remaining
and Ao = the initial amount
and n = t / t(1/2)
by substitution:
∴ A = 200 mg/ 2^(t/30y)b) Mass after 90 y :by  using the previous formula and substitute t by 90 y
A = 200mg/ 2^(90y/30y)
∴ A = 25 mgC) Time for 1 mg remaining:when A= Ao/ 2^(t/t(1/2)
so, by substitution:
1 mg = 200 mg / 2^(t/30y)
∴2^(t/30y) = 200 mg  by solving for t
∴ t = 229 y 
 
        
             
        
        
        
Answer:
12.5mm
Explanation:
1cm = 10mm 
so you need to multiply the 1.25 by 10 to get it in mm.
 
        
             
        
        
        
The AP Biology teacher is measuring out 638.0 g of dextrose (C6H12O6) for a lab the moles of dextrose is this equivalent to is 3.6888 moles.
<h3>What are moles?</h3>
A mole is described as 6.02214076 × 1023 of a few chemical unit, be it atoms, molecules, ions, or others. The mole is a handy unit to apply due to the tremendous variety of atoms, molecules, or others in any substance.
To calculate molar equivalents for every reagent, divide the moles of that reagent through the moles of the restricting reagent. The calculation is follows:
- 655/12 x 6 + 12+ 16 x 6 
- = 655/ 180 = 3.6888 moles.
Read more about moles:
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