In a chemical reaction, ... interact to form ...

which of the following substances is least able to cross the blood-brain barrier.)a. waterb. sodium ionsc glucosed. white blood

ivolga24 [154]

Answer:

d. white blood cells

Explanation:

It is the white blood cells that have the least tendency to cross the blood- brain barrier.

Blood- brain barrier is psychological barrier and restricts substances that circulate into the blood from crossing over the central nervous system.

Water, glucose as well as sodium ions can easily cross the barrier. As these are good for body supply energy to the brain.

8 0

3 years ago

Identify one type of noncovalent bond present in each solid.

NeX [460]

Answer:

Explanation:

The question is not complete, the cmplete question is:

Identify one type of noncovalent bond present in each solid.

1) Table salt (NaCl) 2) Graphite (repeating)

a. hydrogen bonds

b. ionic interactions

c. van der Waals interactions

d. hydrophobic interactions

Answer:

1) Table salt

b. ionic interactions

Ionic bond are formed between atoms with incomplete outermost shell. Some atoms add electrons to their outermost shell to make the shell complete hence making it a negative ion while some atoms loses their electron to make the outermost shell complete becoming a positive ion. In NaCl, sodium (Na) has 1 electron in its outermost shell which it transfers to Cl which has 7 electrons in the outermost shell. Hence after the bonding the outermost shell of the atoms become complete.

2) Graphite

c. Van Der Waals interaction

Van der waal forces are weak interaction between molecules that exist between close atoms. Carbon atoms in graphite planes have covalent bond, these graphite planes are known as graphenes. Bonds between graphenes are very weak and are van der waals forces.

7 0

3 years ago

In a titration of hno3, you add a few drops of phenolphthalein indicator to 50.00 ml of acid in a flask. You quickly add 20.00 m

bekas [8.4K]

Answer:

The HNO3 solution has a concentration of 0.07 M

Explanation:

Step 1: find a balanced equation

HNO3 (aq) + NaOH (aq) → NaNO3 (aq) + H2O (l)

⇒ for 1 mole of HNO3 reacted, there will also react 1 mole of NaOH, and be produced 1 mole of NaNO3 and 1 mole of H2O, since the ratio is 1:1

Step 2: Calculating moles

Since we know that for 1 mole of HNO3 there will react 1 mole of NaOH, we can calculate the number of moleNaOH

⇒ Concentration = mole / volume

⇒ 0.210 = mole / ((20 + 7.23 ml) *10^-3)

mole = 0.005733 mole NaOH = 0.005733 mole HNO3

Step 3: Calculating the concentration of HNO3

Concentration = mole / volume

C(HNO3) = 0.005733 mole / ((50 + 30 ml) *10^-3)

C(HNO3) = 0.07 M

The HNO3 solution has a concentration of 0.07 M

To control this we can calculate through the following formule:

0.02723L x 0.21 M x ( 1mol HNO3 / 1 mol NaOH) x (1/ 0.08L) = 0.07M

8 0

3 years ago

During which step in the pcr cycle do primers form bonds with a single-stranded template?.

shutvik [7]

Answer: The first steps

Explanation: science

5 0

3 years ago

How much carbon will turn into carbon 14 every year? Science Please help asap

saw5 [17]

Answer:

There are three naturally occurring isotopes of carbon on Earth: carbon-12, which makes up 99% of all carbon on Earth; carbon-13, which makes up 1%; and carbon-14, which occurs in trace amounts, making up about 1 or 1.5 atoms per 1012 atoms of carbon in the atmosphere.

Names: carbon-14, C-14, radiocarbon

Isotope mass: 14.003241 u

Half-life: 5,730 ± 40 years

Symbol: 14C

Explanation:

Pls give me brainliest

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5 0

3 years ago