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2 years ago

HELP!! PLEASE! Describe North America’s rotation. (in terms of continental drift)

Chemistry

1 answer:

Zigmanuir [339]2 years ago

3 0

Answer:

https://www.nationalgeographic.org/encyclopedia/continental-drift/#geologic-plates-600mya

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After an hour in the cooler the sodas get colder and the ice gets warmer. Which of the following explains these changes correctl

kompoz [17]

Because it’s called heat changes it and melts the ice

6 0

2 years ago

What is the mass percent of oxygen in sodium bicarbonate (NaHCO3)?

Alenkasestr [34]

The answer is 57.14%.

First we need to calculate molar mass of NaHCO3. Molar mass is mass of 1 mole of a substance. It is the sum of relative atomic masses, which are masses of atoms of the elements.

Relative atomic mass of Na is 22.99 g
Relative atomic mass of H is 1 g
Relative atomic mass of C is 12.01 g
Relative atomic mass of O is 16 g.

Molar mass of NaHCO3 is:
22.99 g + 1 g + 12.01 g + 3 · 16 g = 84 g

Now, mass of oxygen in NaHCO3 is:
3 · 16 g = 48 g

mass percent of oxygen in NaHCO3:
48 g ÷ 84 g · 100% = 57.14%

Therefore, the mass percent of oxygen in sodium bicarbonate is 57.14%.

8 0

2 years ago

The atomic number of Re is 75. The atomic mass of one of its isotopes is 186. How many neutrons are in an atom of this isotope?

USPshnik [31]

Answer:

B.111

Explanation:

Atomic mass = number of protons(or atomic number) + number of neutrons

186 = 75 + number of neutrons

number of neutrons = 186 -75 = 111

7 0

2 years ago

How many grams of h2 will be produced if 175g of HCI are allowed to react completely with sodium

Sedbober [7]

Answer:

4.8 grams of H₂ will be produced if 175g of HCI are allowed to react completely with sodium

Explanation:

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction) you can see that the following amounts in moles of each compound react and are produced:

HCl: 2 moles
Na: 1 mole
NaCl: 2 moles
H₂: 1 mole

You know the following masses of each element:

H: 1 g/mole
Cl: 35.45 g/mole
Na: 23 g/mole

So, the molar mass of each compound participating in the reaction is:

HCl: 1 g/mole + 35.45 g/mole= 36.45 g/mole
Na: 23 g/mole
NaCl: 23 g/mole + 35.45 g/mole= 58.45 g/mole
H₂: 2* 1 g/mole= 2 g/mole

Then, by stoichiometry of the reaction, the following amounts in grams of each of the compounds participating in the reaction react and are produced:

HCl: 2 moles* 36.45 g/mole= 72.9 g
Na: 1 mole* 23 g/mole= 23 g
NaCl: 2 moles* 58.45 g/mole= 116.9 g
H₂: 1 mole* 2 g/mole= 2 g

So, a rule of three applies as follows: if by stoichiometry, when reacting 72.9 grams of HCl 2 grams of H₂ are formed, when reacting 175 grams of HCl how much mass of H₂ will be formed?

$mass of H_{2} =\frac{175 g of HCl*2g ofH_{2} }{72.9 g of HCl}$

mass of H₂= 4.8 g

4.8 grams of H₂ will be produced if 175g of HCI are allowed to react completely with sodium

3 0

2 years ago

Read 2 more answers

A cell with osmolarity measuring 300 mosm/l is placed in a beaker that contains a nacl solution with osmolarity of 150mosm/l. pr

tia_tia [17]

My hypothesis is the the cell, having a higher osmolarity than the solution of of nacl in the beaker, will have an osmosis reaction releasing into the solution of nacl. This will continue until both cell and solution reach a balance.

5 0

2 years ago