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3 years ago

Ill upvote help please

1 answer:

4 0

Hello there.

Natalie accelerates her skateboard along a straight path from 4 m/s to 0 m/s in 25.0 s. Find the acceleration.

0.16 m/s2

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Which of the following is the greatest mass? Select one:

algol13

Answer:

B. 1.000 × 10-4 kg

Explanation:

A. 1.000 × 10-8 Mg = 0.00000001 Mg = 0.1 mg

B. 0.0001 kg = 0.1 g

C. 1000 ug = 1 mg

D. 1 .000 × 10-2 cg = 0.01 cg = 0.1 mg

A = D

B > C > A = D

8 0

3 years ago

What is conditional reflexes??

SIZIF [17.4K]

Answer:

Actions that you have trained yourself to perform.

they are obtained by experience. they are not passed from generation. they can be learnt or abolished. Higher center's of brain is responsible for conditional reflexes

Explanation:

example riding a bike, swimming, typing

6 0

4 years ago

12. How many moles of atoms are present in 154 g of Na2O?

tia_tia [17]

Answer:

$\boxed {\boxed {\sf A. \ 2.48 \ mol \ Na_2O}}$

Explanation:

We are asked to convert an amount in grams to moles. To do this, we use the molar mass. This is the number of grams in one mole of a substance. It is the same value numerically as the atomic mass on the Periodic Table, however the units are grams per mole, not atomic mass units.

Look up the molar masses for the individual elements.

Sodium (Na): 22.9897693 g/mol
Oxygen (O): 15.999 g/mol

Look back at the formula: Na₂O. Notice there is a subscript of 2 after sodium. This means there are 2 atoms of sodium in every molecule, so we have to multiply sodium's molar mass by 2 before adding oxygen's.

Na₂O: 2(22.9897693 g/mol)+ 15.999 g/mol = 61.9785386 g/mol

Set up a ratio using the molar mass.

$\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}$

Multiply by the given number of grams.

$154 \ g \ Na_2O*\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}$

Flip the ratio so the grams of sodium oxide can cancel each other out.

$154 \ g \ Na_2O*\frac {1 \ mol \ Na_2O}{61.9785386 \ g \ Na_2O}$

$154 *\frac {1 \ mol \ Na_2O}{61.9785386 }$

$\frac {154}{61.9785386 } \ mol \ Na_2O$

$2.48473106141 \ mol \ Na_2O$

The original measurement of grams given has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place.

2.48473106141

The 4 in the thousandth place tells us to leave the 8.

$2.48 \ mol \ Na_2O$

There are 2.48 moles of sodium oxide in 154 grams, so choice A is correct.

6 0

3 years ago

Which two rocks are primarily composed of a mineral that bubbles with acid?

Marianna [84]

To most geologists, the term "acid test" means placing a drop of dilute (5% to 10%) hydrochloric acid on a rock or mineral and watching for bubbles of carbon dioxide gas to be released. The bubbles signal the presence of carbonate minerals such ascalcite, dolomite, or one of the minerals listed in Table 1.

8 0

3 years ago

Disadvantages of biodegradable plastics

natita [175]

1) The main disadvantage of bio plastics is that when they break down , carbondioxide is released and results into global warming.

2) They are designed to be composted , not recycled.

3) fewer proper composting availability.

4) plants grown for bioplastics have negative impacts of their own.

4 0

4 years ago