A chemical symbol is a shorthand method of representing an element. Instead of writing out the name of an element, we represent an element name with one or two letters. As you know, the periodic table is a chemist's easy reference guide. ... Each element is represented by a chemical symbol consisting of letters
Answer:
a. Earth casts a shadow on the moon.
Explanation:
Lunar eclipse occurs when Earth comes in between sun and moon. The sunlight falling on moon is blocked by Earth and the shadow of earth falls on moon. This happens on full moon day when sun, earth and moon align in one line.The moon passes through the shadow of earth and appears dark.
Thus, the correct option is a.
start the balancing by writing down how many atoms there are per element. we’ll use this as an example:
C3H8 + O2 --> H2O + CO2
C = 3 C = 1
H = 8 H = 2
O = 2 O = 3
balance the carbon first, as it is easiest to do. add a coefficient to the single carbon atom on the right of the equation to balance it with the 3 carbon atoms on the left of the equation:
C3H8 + O2 --> H2O + (3)CO2
now there are 3 carbon atoms on each side. however, when you do this, you multiply the amount of oxygen atoms you had. therefore, now, there are 6 carbon atoms in 3CO2, plus that other oxygen atom in H2O. you now have 7 O atoms instead of 3.
C = 3 C = 3
H = 8 H = 2
O = 2 O = 7
now let’s move on to the hydrogen atoms.
C3H8 + O2 --> H2O + 3CO2
you have 8 hydrogen atoms on the left side, and 2 on the right. in order to balance them, you have to multiply the right side’s hydrogen atoms by 4. 4(2) = 8.
C3H8 + O2 --> (4)H2O + 3CO2
now both hydrogen and carbon atoms are balanced. same amount on both sides. however, your oxygen atoms have changed due to the multiplying (right side). you now have 10 of them.
C = 3 C = 3
H = 8 H = 8
O = 2 O = 10
now we balance the oxygen atoms. multiply the left side of the equation’s oxygen atoms by 5. 5(2) = 10
C3H8 + (5)O2 --> 4H2O + 3CO2
the chemical equation is all balanced. basically, just multiply with numbers until it equals the same amount on both sides.
C = 3 C = 3
H = 8 H = 8
O = 10 O = 10
Answer:
= 498.13 mmHg
Explanation:
Using the combined gas law;
P1V1/T1 =P2V2/T2
in this case; P1 = 725 mmHg, V1 = 375 mL and T1 = 25°C + 273 = 298 K
P2 = ? V2 = 500 mL and T2 (standard temperature) = 0°C + 273 = 273 K
P2 = P1V1T2/T1V2
= (725 × 375 × 273)/(298 × 500)
<u>= 498.13 mmHg </u>
Molar mass = 133.34 g/mol
